WorldWideScience

Sample records for nested fixed-depth fluidic

  1. Nested Fixed Depth Fluidic Sampler and At Tank Analysis System Deployment Strategy and Plan

    Energy Technology Data Exchange (ETDEWEB)

    REICH, F.R.

    2000-02-01

    Under the Hanford Site River Protection Project (RPP) privatization strategy, the U.S. Department of Energy (DOE) Office of River Protection (ORP) requires the CH2M Hill Hanford Group, Inc. (CHG) to supply tank waste to the privatization contractor, BNFL Inc. (BNFL), for separation and/or treatment and immobilization (vitrification). Three low-activity waste (LAW) specification envelopes represent the range of liquid waste types in the large, Hanford Site underground waste storage tanks. The CHG also is expected to supply high-level waste (HLW) separation and/or treatment and disposal. The HLW envelope is an aqueous slurry of insoluble suspended solids (sludge). The Phase 1 demonstration will extend over 24 years (1996 through 2019) and will be used to resolve technical uncertainties. About one-tenth of the total Hanford Site tank waste, by mass, will be processed during this period. This document provides a strategy and top-level implementation plan for demonstrating and deploying an alternative sampling technology. The alternative technology is an improvement to the current grab sampling and core sampling approaches that are planned to be used to support the RPP privatization contract. This work also includes adding the capability for some at-tank analysis to enhance the potential of this new technology to meet CHG needs. The first application is to LAW and HLW feed staging for privatization; the next is to support cross-site waste transfer from 200 West Area tanks.

  2. Formation and Control of Fluidic Species

    Science.gov (United States)

    Link, Darren Roy (Inventor); Weitz, David A. (Inventor); Marquez-Sanchez, Manuel (Inventor); Cheng, Zhengdong (Inventor)

    2015-01-01

    This invention generally relates to systems and methods for the formation and/or control of fluidic species, and articles produced by such systems and methods. In some cases, the invention involves unique fluid channels, systems, controls, and/or restrictions, and combinations thereof. In certain embodiments, the invention allows fluidic streams (which can be continuous or discontinuous, i.e., droplets) to be formed and/or combined, at a variety of scales, including microfluidic scales. In one set of embodiments, a fluidic stream may be produced from a channel, where a cross-sectional dimension of the fluidic stream is smaller than that of the channel, for example, through the use of structural elements, other fluids, and/or applied external fields, etc. In some cases, a Taylor cone may be produced. In another set of embodiments, a fluidic stream may be manipulated in some fashion, for example, to create tubes (which may be hollow or solid), droplets, nested tubes or droplets, arrays of tubes or droplets, meshes of tubes, etc. In some cases, droplets produced using certain embodiments of the invention may be charged or substantially charged, which may allow their further manipulation, for instance, using applied external fields. Non-limiting examples of such manipulations include producing charged droplets, coalescing droplets (especially at the microscale), synchronizing droplet formation, aligning molecules within the droplet, etc. In some cases, the droplets and/or the fluidic streams may include colloids, cells, therapeutic agents, and the like.

  3. Fluidic nanotubes and devices

    Science.gov (United States)

    Yang, Peidong; He, Rongrui; Goldberger, Joshua; Fan, Rong; Wu, Yiying; Li, Deyu; Majumdar, Arun

    2008-04-08

    Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

  4. Magnetohydrodynamic fluidic system

    Science.gov (United States)

    Lee, Abraham P.; Bachman, Mark G.

    2004-08-24

    A magnetohydrodynamic fluidic system includes a reagent source containing a reagent fluid and a sample source containing a sample fluid that includes a constituent. A reactor is operatively connected to the supply reagent source and the sample source. MHD pumps utilize a magnetohydrodynamic drive to move the reagent fluid and the sample fluid in a flow such that the reagent fluid and the sample fluid form an interface causing the constituent to be separated from the sample fluid.

  5. MEMS fluidic actuator

    Science.gov (United States)

    Kholwadwala, Deepesh K.; Johnston, Gabriel A.; Rohrer, Brandon R.; Galambos, Paul C.; Okandan, Murat

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  6. Sampling by Fluidics and Microfluidics

    Directory of Open Access Journals (Sweden)

    V. Tesař

    2002-01-01

    Full Text Available Selecting one from several available fluid samples is a procedure often performed especially in chemical engineering. It is usually done by an array of valves sequentially opened and closed. Not generally known is an advantageous alternative: fluidic sampling units without moving parts. In the absence of complete pipe closure, cross-contamination between samples cannot be ruled out. This is eliminated by arranging for small protective flows that clear the cavities and remove any contaminated fluid. Although this complicates the overall circuit layout, fluidic sampling units with these "guard" flows were successfully built and tested. Recent interest in microchemistry leads to additional problems due very low operating Reynolds numbers. This necessitated the design of microfluidic sampling units based on new operating principles.

  7. Centrifuge-Based Fluidic Platforms

    Science.gov (United States)

    Zoval, Jim; Jia, Guangyao; Kido, Horacio; Kim, Jitae; Kim, Nahui; Madou, Marc

    In this chapter centrifuge-based microfluidic platforms are reviewed and compared with other popular microfluidic propulsion methods. The underlying physical principles of centrifugal pumping in microfluidic systems are presented and the various centrifuge fluidic functions such as valving, decanting, calibration, mixing, metering, heating, sample splitting, and separation are introduced. Those fluidic functions have been combined with analytical measurements techniques such as optical imaging, absorbance and fluorescence spectroscopy and mass spectrometry to make the centrifugal platform a powerful solution for medical and clinical diagnostics and high-throughput screening (HTS) in drug discovery. Applications of a compact disc (CD)-based centrifuge platform analyzed in this review include: two-point calibration of an optode-based ion sensor, an automated immunoassay platform, multiple parallel screening assays and cellular-based assays. The use of modified commercial CD drives for high-resolution optical imaging is discussed as well. From a broader perspective, we compare the technical barriers involved in applying microfluidics for sensing and diagnostic as opposed to applying such techniques to HTS. The latter poses less challenges and explains why HTS products based on a CD fluidic platform are already commercially available, while we might have to wait longer to see commercial CD-based diagnostics.

  8. Indexing film with a fluidic sensor

    Science.gov (United States)

    Maciel, A., Jr.

    1972-01-01

    Fluidic sensor is used to measure passage of film without mechanical contact with counting device. Same sensor system may be used for different sizes of film. System has two fluidic sensors and operates on principle of electrically recording interruptions in air stream.

  9. Separation control with fluidic oscillators in water

    Science.gov (United States)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2017-08-01

    The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

  10. Triangular Nests!

    Science.gov (United States)

    Powell, R. I.

    2002-01-01

    Shows how integer-sided triangles can be nested, each nest having a single enclosing isosceles triangle. Brings to light what can be seen as a relatively simple generalization of Pythagoras' theorem, a result that should be readily accessible to many secondary school pupils. (Author/KHR)

  11. Water oxygenation by fluidic microbubble generator

    Directory of Open Access Journals (Sweden)

    Tesař V

    2014-03-01

    Full Text Available Oxygenation of water by standard means in waste water processing, in particular to improve the conditions for the micro-organisms that decompose organic wastes is rather ineffective. The classical approach to improvements – decreasing the size of the aerator exits - have already reached their limits. A recent new idea is to decrease the size of the generated air bubbles by oscillating the supplied air flow using fluidic oscillators. Authors made extensive performance measurements with an unusual high-frequency fluidic oscillator, designed to operate within the submersed aerator body. The performance was evaluated by the dynamic method of recording the oxygen concentration increase to saturation in the aerated water. Experiments proved the fluidic generator can demonstrably increase the aeration efficiency 4.22-times compared with the aeration from a plain end of a submerged air supply tube. Despite this significant improvement, the behaviour of the generator still provides an opportunity for further improvements.

  12. Solvent-free fluidic organic dye lasers.

    Science.gov (United States)

    Choi, Eun Young; Mager, Loic; Cham, Tran Thi; Dorkenoo, Kokou D; Fort, Alain; Wu, Jeong Weon; Barsella, Alberto; Ribierre, Jean-Charles

    2013-05-06

    We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green- and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Förster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors.

  13. Adjustable fluidic lenses for ophthalmic corrections.

    Science.gov (United States)

    Marks, Randall; Mathine, David L; Peyman, Gholam; Schwiegerling, Jim; Peyghambarian, Nasser

    2009-02-15

    We report on two fluidic lenses that have been developed for ophthalmic applications. The lenses use a circular aperture to demonstrate optical powers between -20 and +20 D and a rectangular aperture to demonstrate astigmatism with values ranging from 0 to 8 D. Measurements of image quality were made with the fluidic lens using a model eye. Both lenses were variable and controllable by adjusting the fluid volume of the lens. To the best of our knowledge this is the first demonstration of a continuously variable lens for control of astigmatism.

  14. Fluidic Elements based on Coanda Effect

    Directory of Open Access Journals (Sweden)

    Constantin OLIVOTTO

    2010-12-01

    Full Text Available This paper contains first some definitions and classifications regarding the fluidic elements. Thegeneral current status is presented, nominating the main specific elements based on the Coanda effect developedspecially in Romania. In particularly the development of an original bistable element using industrial compressedair at industrial pressure supply is presented. The function of this element is based on the controlled attachmentof the main jet at a curved wall through the Coanda effect. The methods used for particular calculation andexperiments are nominated. The main application of these elements was to develop a specific execution element:a fluidic step–by-step motor based on the Coanda effect.

  15. Fluidic interconnections for microfluidic systems: A new integrated fluidic interconnection allowing plug 'n' play functionality

    DEFF Research Database (Denmark)

    Perozziello, Gerardo; Bundgaard, Frederik; Geschke, Oliver

    2008-01-01

    A crucial challenge in packaging of microsystems is microfluidic interconnections. These have to seal the ports of the system, and have to provide the appropriate interface to other devices or the external environment. Integrated fluidic interconnections appear to be a good solution...... for interconnecting polymer microsystems in terms of cost, space and performance. Following this path we propose a new reversible, integrated fluidic interconnection composed of custom-made cylindrical rings integrated in a polymer house next to the fluidic network. This allows plug 'n' play functionality between...... external metal ferrules and the system. Theoretical calculations are made to dimension and model the integrated fluidic interconnection. Leakage tests are performed on the interconnections, in order to experimentally confirm the model, and detect its limits....

  16. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

    2003-01-01

    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...

  17. Numerical modeling of fluidic flow meters

    Science.gov (United States)

    Choudhury, D.; Patel, B. R.

    1992-05-01

    The transient fluid flow in fluidic flow meters has been modeled using Creare.x's flow modeling computer program FLUENT/BFC that solves the Navier-Stokes equations in general curvilinear coordinates. The numerical predictions of fluid flow in a fluidic flow meter have been compared with the available experimental results for a particular design, termed the PC-4 design. Overall flow structures such as main jet bending, and primary and secondary vortices predicted by FLUENT/BFC are in excellent agreement with flow visualization results. The oscillation frequencies of the PC-4 design have been predicted for a range of flow rates encompassing laminar and turbulent flow and the results are in good agreement with experiments. The details of the flow field predictions reveal that an important factor that determines the onset of oscillations in the fluidic flow meter is the feedback jet momentum relative to the main jet momentum. The insights provided by the analysis of the PC-4 fluidic flow meter design have led to an improved design. The improved design has sustained oscillations at lower flow rates compared with the PC-4 design and has a larger rangeability.

  18. Directed Autonomic Flow : Functional Motility Fluidics

    NARCIS (Netherlands)

    Kuehn, Philipp T.; de Miranda, Barbara Santos; van Rijn, Patrick

    2015-01-01

    Unidirectional coherent motion of a self-moving droplet is achieved and combined in a functional motility fluidic chip for chemical reactions via a novel and straightforward approach. The droplet shows both increased movement speeds and displacement distances without any input of energy. Nanoparticl

  19. Hawaii ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird nesting colonies in coastal Hawaii. Vector points in this data set represent locations of...

  20. Louisiana ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird and wading bird nesting colonies in coastal Louisiana. Vector points in this data set represent...

  1. Performance Study of a Fluidic Hammer Controlled by an Output-Fed Bistable Fluidic Oscillator

    Directory of Open Access Journals (Sweden)

    Xinxin Zhang

    2016-10-01

    Full Text Available Using a no-moving-component output-fed bistable fluidic oscillator to control fluid flows into a parallel path has been recognized for a considerable time, but as yet it is not so widely adopted as its obvious benefits would deserve. This may be attributed to the encountered problems associated with its jet behavior, complicated by its loading characteristics. In order to investigate a typical case for the application of the output-fed fluidic oscillator, this paper elaborates on the computational fluid dynamics (CFD simulation method for studying the performance of a fluidic hammer controlled by an output-fed bistable fluidic oscillator. Given that couple mechanism exists between the flow field in the fluidic oscillator and the impact body, dynamic mesh technique and a user-defined function written in C programming language were used to update the mesh in the simulations. In terms of the evaluation of performance, the focus is on the single-impact energy and output power of the fluidic hammer in this study, to investigate the effect of different parameters of the impact body on them. Experimental tests based on the noncontact measuring method were conducted to verify the simulation results, by which the accuracy and reliability of this CFD simulation method was proved.

  2. An implantable fluidic vibrational energy harvester

    Science.gov (United States)

    Inoue, S.; Takahashi, T.; Kumemura, M.; Fujita, H.; Toshiyoshi, H.

    2016-11-01

    Targeting implantable medical devices such as respiratory pace-maker, we have developed a proof-of-concept level energy harvester device that could earn electric power of 44 μW/cm2 by the fluidic motion in a PDMS microchannel placed on a silicon substrate with built-in permanent electrical charges or so-called electrets. The motion of the working fluid will be operated by the heart beat or breathing as a final shape of the energy harvesting system.

  3. 3D Printed Fluidic Hardware for DNA Assembly

    Science.gov (United States)

    2015-04-10

    printed parts. The 3D printed parts were designed in SolidWorks and printed using the Makerbot Replicator 2X. The printed parts are modular, enabling...this study had multiple years of experience working with SolidWorks . Many biologists interested in designing fluidics will likely not have similar...Methods Designing & 3D printing fluidics All fluidic devices were designed using SolidWorks . STL files were generated in SolidWorks . For 3D printing

  4. DNA Assembly in 3D Printed Fluidics.

    Directory of Open Access Journals (Sweden)

    William G Patrick

    Full Text Available The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology.

  5. Dielectric Elastomers for Fluidic and Biomedical Applications

    Science.gov (United States)

    McCoul, David James

    Dielectric elastomers have demonstrated tremendous potential as high-strain electromechanical transducers for a myriad of novel applications across all engineering disciplines. Because their soft, viscoelastic mechanical properties are similar to those of living tissues, dielectric elastomers have garnered a strong foothold in a plethora of biomedical and biomimetic applications. Dielectric elastomers consist of a sheet of stretched rubber, or elastomer, coated on both sides with compliant electrode materials; application of a voltage generates an electrostatic pressure that deforms the elastomer. They can function as soft generators, sensors, or actuators, and this last function is the focus of this dissertation. Many design configurations are possible, such as stacks, minimum energy structures, interpenetrating polymer networks, shape memory dielectric elastomers, and others; dielectric elastomers are already being applied to many fields of biomedicine. The first part of the original research presented in this dissertation details a PDMS microfluidic system paired with a dielectric elastomer stack actuator of anisotropically prestrained VHB(TM) 4910 (3M(TM)) and single-walled carbon nanotubes. These electroactive microfluidic devices demonstrated active increases in microchannel width when 3 and 4 kV were applied. Fluorescence microscopy also indicated an accompanying increase in channel depth with actuation. The cross-sectional area strains at 3 and 4 kV were approximately 2.9% and 7.4%, respectively. The device was then interfaced with a syringe pump, and the pressure was measured upstream. Linear pressure-flow plots were developed, which showed decreasing fluidic resistance with actuation, from 0.192 psi/(microL/min) at 0 kV, to 0.160 and 0.157 psi/(microL/min) at 3 and 4 kV, respectively. This corresponds to an ~18% drop in fluidic resistance at 4 kV. Active de-clogging was tested in situ with the device by introducing ~50 microm diameter PDMS microbeads and

  6. American Samoa ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in American Samoa. Vector points in this data set represent locations of nesting...

  7. Low-cost thermoforming of micro fluidic analysis chips

    Science.gov (United States)

    Truckenmüller, R.; Rummler, Z.; Schaller, Th; Schomburg, W. K.

    2002-07-01

    We present a new method for the low-cost manufacture of micro fluidic devices from polymers for single use. Within a one-step or two-step process inside a hot embossing press, micro channels are thermoformed into a thin plastic film and welded on to a thicker plastic film or sheet. Sterile, hermetically sealed micro fluidic structures were fabricated from polystyrene for easy opening immediately before use. It even appears to be possible to produce micro fluidic analysis chips from polymers on a coil from which single devices are cut off for use.

  8. Stability of flowing open fluidic channels

    Directory of Open Access Journals (Sweden)

    Jue Nee Tan

    2013-02-01

    Full Text Available Open fluidic systems have a distinct advantage over enclosed channels in that the fluids exposed nature makes for easy external interaction, this finds uses in introduction of samples by adding liquid droplets or from the surrounding gaseous medium. This work investigates flowing open channels and films, which can potentially make use of the open section of the system as an external interface, before bringing the sample into an enclosed channel. Clearly, in this scenario a key factor is the stability of the flowing open fluid. The open channels investigated include a straight open channel defined by a narrow strip of solid surface, the edges of which allow large contact angle hysteresis, and a wider structure allowing for multiple inputs and outputs. A model is developed for fluid flow, and the findings used to describe the process of failure in both cases.

  9. Compact Fluidic Actuator Arrays For Flow Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of the proposed research is to design, develop and demonstrate fluidic actuator arrays for aerodynamic separation control and drag reduction....

  10. Compact Fluidic Actuator Arrays for Flow Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of the proposed research is to design, develop and demonstrate fluidic actuator arrays for aerodynamic separation control and drag reduction....

  11. Topology optimization of flexible micro-fluidic devices

    DEFF Research Database (Denmark)

    Kreissl, Sebastian; Pingen, Georg; Evgrafov, Anton;

    2010-01-01

    A multi-objective topology optimization formulation for the design of dynamically tunable fluidic devices is presented. The flow is manipulated via external and internal mechanical actuation, leading to elastic deformations of flow channels. The design objectives characterize the performance...

  12. Fluidic Integration of Nanophotonic Devices Using Decomposable Polymers

    CERN Document Server

    Hosseini, Ehsan Shah; Kohl, Paul; Adibi, Ali

    2015-01-01

    Polynorbornene-based decomposable polymer which can be patterned with ultraviolet or electron-beam radiation is used to create micrometer-scale fluidic channels. Silicon nitride substrates are used to fabricate nanophotonic wavegide and resonators operating in the visible range of the spectrum. Fluidic channels generated by thermally decomposing the polymer through the oxide cladding is used to deliver ultra-small amounts of florescent samples to the optical sensors.

  13. Electronics plus fluidics for V/STOL flight control

    Science.gov (United States)

    Hendrick, R. C.

    1977-01-01

    The redundant digital fly by wire flight control system coupled with a fluidic system, which uses hydraulic pressure as its signal transmission means to provide pilot and feedback sensor control of airframe forcing functions is considered for application to the V/STOL aircraft. A potential fluidics system is introduced, and anticipated performance, weight, and reliability is discussed. Integration with the redundant electronic channels is explored, with the safety and mission reliability of alternate configurations estimated.

  14. A Coupled Cavity Micro Fluidic Dye Ring Laser

    CERN Document Server

    Gersborg-Hansen, M; Mortensen, N A; Kristensen, A

    2004-01-01

    We present a laterally emitting, coupled cavity micro fluidic dye ring laser, suitable for integration into lab-on-a-chip micro systems. The micro-fluidic laser has been successfully designed, fabricated, characterized and modelled. The resonator is formed by a micro-fluidic channel bounded by two isosceles triangle mirrors. The micro-fluidic laser structure is defined using photo lithography in 10 microns thick SU-8 polymer on a glass substrate. The micro fluidic channel is sealed by a glass lid, using PMMA adhesive bonding. The laser is characterized using the laser dye Rhodamine 6G dissolved in ethanol or ethylene glycol as the active gain medium, which is pumped through the micro-fluidic channel and laser resonator. The dye laser is optically pumped normal to the chip plane at 532 nm by a pulsed, frequency doubled Nd:YAG laser and lasing is observed with a threshold pump pulse energy flux of around 55 micro-Joule/square-milimeter. The lasing is multi-mode, and the laser has switchable output coupling into...

  15. Integration of fluidic jet actuators in composite structures

    Science.gov (United States)

    Schueller, Martin; Lipowski, Mathias; Schirmer, Eckart; Walther, Marco; Otto, Thomas; Geßner, Thomas; Kroll, Lothar

    2015-04-01

    Fluidic Actuated Flow Control (FAFC) has been introduced as a technology that influences the boundary layer by actively blowing air through slots or holes in the aircraft skin or wind turbine rotor blade. Modern wing structures are or will be manufactured using composite materials. In these state of the art systems, AFC actuators are integrated in a hybrid approach. The new idea is to directly integrate the active fluidic elements (such as SJAs and PJAs) and their components in the structure of the airfoil. Consequently, the integration of such fluidic devices must fit the manufacturing process and the material properties of the composite structure. The challenge is to integrate temperature-sensitive active elements and to realize fluidic cavities at the same time. The transducer elements will be provided for the manufacturing steps using roll-to-roll processes. The fluidic parts of the actuators will be manufactured using the MuCell® process that provides on the one hand the defined reproduction of the fluidic structures and, on the other hand, a high light weight index. Based on the first design concept, a demonstrator was developed in order to proof the design approach. The output velocity on the exit was measured using a hot-wire anemometer.

  16. Tubular astigmatism-tunable fluidic lens.

    Science.gov (United States)

    Kopp, Daniel; Zappe, Hans

    2016-06-15

    We demonstrate a new means to fabricate three-dimensional liquid lenses which may be tuned in focal length and astigmatism. Using actuation by electrowetting-on-dielectrics, astigmatism in arbitrary directions may be tuned independently, with almost no cross talk between orthogonal orientations. The lens is based on electrodes structured on planar polyimide foils and subsequently rolled, enabling high-resolution patterning of complex electrodes along the azimuthal and radial directions of the lens. Based on a design established through fluidic and optical simulations, the astigmatism tuning is experimentally verified by a change of the corresponding Zernike coefficients measured using a Shack-Hartmann wavefront sensor. It was seen that the back focal length can be tuned by 5 mm and 0° and 45° astigmatism by 3 μm through application of voltages in the range of 50  Vrms. It was observed that the cross talk with other aberrations is very low, suggesting a novel means for astigmatism control in imaging systems.

  17. Measurement of microchannel fluidic resistance with a standard voltage meter.

    Science.gov (United States)

    Godwin, Leah A; Deal, Kennon S; Hoepfner, Lauren D; Jackson, Louis A; Easley, Christopher J

    2013-01-03

    A simplified method for measuring the fluidic resistance (R(fluidic)) of microfluidic channels is presented, in which the electrical resistance (R(elec)) of a channel filled with a conductivity standard solution can be measured and directly correlated to R(fluidic) using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R(fluidic) to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600kPa smm(-3)) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R(fluidic) measurements were possible in more complex microfluidic designs. Microchannel R(elec) was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. A characteristic analysis of the fluidic muscle cylinder

    Science.gov (United States)

    Kim, Dong-Soo; Bae, Sang-Kyu; Hong, Sung-In

    2005-12-01

    The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.

  19. Recruitment study nest card

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a survey on waterfowl nests in Stillwater Wildlife Management Area. Visits were made to each nest on an approximately weekly basis, and the stage of the eggs...

  20. Simulated nest study guide

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The instructions outlined here will provide uniform methods for measuring total predator activity in blocks of nesting cover or at special kinds of nest sites. The...

  1. Fluidics platform and method for sample preparation and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

    2014-08-19

    Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

  2. A generalized optimization principle for asymmetric branching in fluidic networks

    Science.gov (United States)

    Stephenson, David; Lockerby, Duncan A.

    2016-07-01

    When applied to a branching network, Murray's law states that the optimal branching of vascular networks is achieved when the cube of the parent channel radius is equal to the sum of the cubes of the daughter channel radii. It is considered integral to understanding biological networks and for the biomimetic design of artificial fluidic systems. However, despite its ubiquity, we demonstrate that Murray's law is only optimal (i.e. maximizes flow conductance per unit volume) for symmetric branching, where the local optimization of each individual channel corresponds to the global optimum of the network as a whole. In this paper, we present a generalized law that is valid for asymmetric branching, for any cross-sectional shape, and for a range of fluidic models. We verify our analytical solutions with the numerical optimization of a bifurcating fluidic network for the examples of laminar, turbulent and non-Newtonian fluid flows.

  3. A review on optical microfibers in fluidic applications

    Science.gov (United States)

    Yan, Shao-cheng; Xu, Fei

    2017-09-01

    Fiber-based opto-fluidics with the distinct benefit of alignment-free optics has been a new rising area by integrating optical fiber and microfluidics in recent years. Optical microfibers with large accessible evanescent field and great configurability have more advantages on the integration with microfluidics than traditional fibers. Based on the strong light-liquid interaction, the fluid has the ability to modulate optical microfiber devices by changing physical and chemical properties such as refractive index, temperature, flow rate, chemicals dissolved in the fluid, etc. The light in the microfiber can also be used to manipulate particles which can move in the fluidic channel. Here we review the broad opto-fluidic applications of optical microfibers such as measurement of liquid characteristics, nonlinear effects, laser generation and optical manipulations with miniaturization, low cost, and high sensitivity. The microfiber-based microfluidic platform may provide more strategies for physical and chemical sensing applications and in particular contactless optical diagnostics.

  4. Columbia River ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for bird nesting sites in the Columbia River area. Vector points in this data set represent locations of...

  5. PyMultiNest: Python interface for MultiNest

    Science.gov (United States)

    Buchner, Johannes

    2016-06-01

    PyMultiNest provides programmatic access to MultiNest (ascl:1109.006) and PyCuba, integration existing Python code (numpy, scipy), and enables writing Prior & LogLikelihood functions in Python. PyMultiNest can plot and visualize MultiNest's progress and allows easy plotting, visualization and summarization of MultiNest results. The plotting can be run on existing MultiNest output, and when not using PyMultiNest for running MultiNest.

  6. Fabrication of resonant micro cantilevers with integrated transparent fluidic channel

    DEFF Research Database (Denmark)

    Khan, Faheem; Schmid, Silvan; Davis, Zachary James

    2011-01-01

    be visually observed through the transparent fluidic channel. The resonant frequency of the cantilever is changed by the fluid inside the channel, due to the change in mass. The shift in the resonant frequency can be translated into a density of the fluid or into the presence of macro/micro molecules...

  7. Rapid development of paper-based fluidic diagnostic devices

    CSIR Research Space (South Africa)

    Smith, S

    2014-11-01

    Full Text Available We present a method for rapid and low-cost development of microfluidic diagnostic devices using paper-based techniques. Specifically, the implementation of fluidic flow paths and electronics on paper are demonstrated, with the goal of producing...

  8. Dynamics of fluidic devices with applications to rotor pitch links

    Science.gov (United States)

    Scarborough, Lloyd H., III

    Coupling a Fluidic Flexible Matrix Composite (F2MC) to an air-pressurized fluid port produces a fundamentally new class of tunable vibration isolator. This fluidlastic device provides significant vibration reduction at an isolation frequency that can be tuned over a broad frequency range. The material properties and geometry of the F2MC element, as well as the port inertance, determine the isolation frequency. A unique feature of this device is that the port inertance depends on pressure so the isolation frequency can be adjusted by changing the air pressure. For constant port inertance, the isolation frequency is largely independent of the isolated mass so the device is robust to changes in load. A nonlinear model is developed to predict isolator length and port inertance. The model is linearized and the frequency response calculated. Experiments agree with theory, demonstrating a tunable isolation range from 9 Hz to 36 Hz and transmitted force reductions of up to 60 dB at the isolation frequency. Replacing rigid pitch links on rotorcraft with coupled fluidic devices has the potential to reduce the aerodynamic blade loads transmitted through the pitch links to the swashplate. Analytical models of two fluidic devices coupled with three different fluidic circuits are derived. These passive fluidlastic systems are tuned, by varying the fluid inertances and capacitances of each fluidic circuit, to reduce the transmitted pitch-link loads. The different circuit designs result in transmitted pitch link loads reduction at up to three main rotor harmonics. The simulation results show loads reduction at the targeted out-of-phase and in-phase harmonics of up to 88% and 93%, respectively. Experimental validation of two of the fluidic circuits demonstrates loads reduction of up to 89% at the out-of-phase isolation frequencies and up to 81% at the in-phase isolation frequencies. Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional

  9. Morphology of nested fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Srolovitz, D.J.; Safran, S.A.; Homyonfer, M.; Tenne, R. (Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel))

    1995-03-06

    We introduce a continuum model which shows that dislocations and/or grain boundaries are intrinsic features of nested fullerenes whose thickness exceeds a critical value to relieve the large inherent strains in these structures. The ratio of the thickness to the radius of the nested fullerenes is determined by the ratio of the surface to curvature and dislocation (or grain boundary) energies. Confirming experimental evidence is presented for nested fullerenes with small thicknesses and with spherosymmetric shapes.

  10. pH-Sensitive Hydrogel for Micro-Fluidic Valve

    Directory of Open Access Journals (Sweden)

    Zhengzhi Yang

    2012-07-01

    Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

  11. Characterizing fluidic seals for on-board reagent delivery

    Science.gov (United States)

    Inamdar, Tejas; Anthony, Brian W.

    2013-03-01

    The reagent delivery mechanism in a point-of-care, HIV diagnostic, microfluidic device is studied. Reagents held in an aluminum blister pack are released on the opening of a fluidic seal. The fluidic seals, controlling the flow of reagents, are characterized to reduce anomalies in the desired flow pattern. The findings of this research can be divided into three categories - 1) bonding phenomenon 2) influence of seal pattern on flow and rupture mechanics and 3) process parameters which minimize flow anomalies. Four seal patterns - line hemisphere, line flat, chevron hemisphere and chevron flat were created and tested for reagent delivery using a flow sensor and a force gauge. Experiments suggest that one of the patterns - line-flat - inducted the fewest flow anomalies. A parameter scoping exercise of the seal manufacturing process parameters (temperature, time, pressure) was performed for the line flat seal. Temperature, time, pressure / gap and distance settings which minimize flow anomalies were found.

  12. Microfluidic hubs, systems, and methods for interface fluidic modules

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Michael S; Claudnic, Mark R; Kim, Hanyoup; Patel, Kamlesh D; Renzi, Ronald F; Van De Vreugde, James L

    2015-01-27

    Embodiments of microfluidic hubs and systems are described that may be used to connect fluidic modules. A space between surfaces may be set by fixtures described herein. In some examples a fixture may set substrate-to-substrate spacing based on a distance between registration surfaces on which the respective substrates rest. Fluidic interfaces are described, including examples where fluid conduits (e.g. capillaries) extend into the fixture to the space between surfaces. Droplets of fluid may be introduced to and/or removed from microfluidic hubs described herein, and fluid actuators may be used to move droplets within the space between surfaces. Continuous flow modules may be integrated with the hubs in some examples.

  13. Development of a continuous-flow fluidic pump

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, S.M.

    1985-08-01

    A study was made of a fluidic pump which utilizes gas pistons, a venturi-like reverse-flow-diverter, and a planar Y-type flow junction to produce a continuous flow of liquid from a system containing no moving parts. The study included an evaluation of the system performance and of methods for controlling the stability of the fluidic system. A mathematical model of the system was developed for steady-state operation using accepted theories of fluid mechanics. Although more elaborate models are needed for detailed design and optimization of specific systems, the model determined some of the main factors controlling the system performance and will be used in the development of more accurate models. 49 refs., 39 figs., 9 tabs.

  14. Opto-bio-fluidic modeling of bioanalytical and biomedical microdevices

    Science.gov (United States)

    Przekwas, Andrzej J.; Sikorski, Zbigniew

    2006-08-01

    Optical technology is rapidly finding novel applications in several exiting bioanalytical, biological, and biomedical applications. Optical beams are increasingly used for bio-fluidic sample manipulation in BioMEMS devices replacing convectional mechanical, electrostatic, and electrokinetic methods. This paper presents novel multiphysics computational approach for modeling optical interaction with fluidic, thermal, mechanical, and biological processes. We present a model of optical manipulation of particles and biological cells with laser beams. Computational results are compared to available experimental data from laboratory experiments and from practical engineered optical bio microdevices. The modeling approach is demonstrated on selected specific applications of optical manipulation of micro spheres, micro cylinders, and optical manipulation and sorting of biological cells in microfluidic cytometers.

  15. Microgravity Boiling Enhancement Using Vibration-Based Fluidic Technologies

    Science.gov (United States)

    Smith, Marc K.; Glezer, Ari; Heffington, Samuel N.

    2002-11-01

    Thermal management is an important subsystem in many devices and technologies used in a microgravity environment. The increased power requirements of new Space technologies and missions mean that the capacity and efficiency of thermal management systems must be improved. The current work addresses this need through the investigation and development of a direct liquid immersion heat transfer cell for microgravity applications. The device is based on boiling heat transfer enhanced by two fluidic technologies developed at Georgia Tech. The first of these fluidic technologies, called vibration-induced bubble ejection, is shown in Fig. 1. Here, an air bubble in water is held against a vibrating diaphragm by buoyancy. The vibrations at 440 Hz induce violent oscillations of the air/water interface that can result in small bubbles being ejected from the larger air bubble (Fig. 1a) and, simultaneously, the collapse of the air/water interface against the solid surface (Fig. 1b). Both effects would be useful during a heat transfer process. Bubble ejection would force vapor bubbles back into the cooler liquid so that they can condense. Interfacial collapse would tend to keep the hot surface wet thereby increasing liquid evaporation and heat transfer to the bulk liquid. Figure 2 shows the effect of vibrating the solid surface at 7.6 kHz. Here, small-scale capillary waves appear on the surface of the bubble near the attachment point on the solid surface (the grainy region). The vibration produces a net force on the bubble that pushes it away from the solid surface. As a result, the bubble detaches from the solid and is propelled into the bulk liquid. This force works against buoyancy and so it would be even more effective in a microgravity environment. The benefit of the force in a boiling process would be to push vapor bubbles off the solid surface, thus helping to keep the solid surface wet and increasing the heat transfer. The second fluidic technology to be employed in this

  16. Fluidic vortices generated from optical vortices in a microdroplet cavity

    CERN Document Server

    Bar-David, Daniel; Martin, Leoplodo L; Carmon, Tal

    2016-01-01

    We harness the momentum of light resonating inside a micro-droplet cavity, to experimentally generate micro-flows within the envelope of the drop. We 3D map these optically induced flows by using fluorescent nanoparticles; which reveals circular micro-streams. The flows are parametrically studied and, as expected, exhibit an increase of rotation speed with optical power. The flow is non-circular only when we intentionally break the axial symmetry of the droplet. Besides the fundamental interest in light-flow interactions including in opto-fluidic cavities, the optically controlled flows can serve in bringing analytes into the maximum-power region of the microcavity.

  17. Superposition Enhanced Nested Sampling

    Directory of Open Access Journals (Sweden)

    Stefano Martiniani

    2014-08-01

    Full Text Available The theoretical analysis of many problems in physics, astronomy, and applied mathematics requires an efficient numerical exploration of multimodal parameter spaces that exhibit broken ergodicity. Monte Carlo methods are widely used to deal with these classes of problems, but such simulations suffer from a ubiquitous sampling problem: The probability of sampling a particular state is proportional to its entropic weight. Devising an algorithm capable of sampling efficiently the full phase space is a long-standing problem. Here, we report a new hybrid method for the exploration of multimodal parameter spaces exhibiting broken ergodicity. Superposition enhanced nested sampling combines the strengths of global optimization with the unbiased or athermal sampling of nested sampling, greatly enhancing its efficiency with no additional parameters. We report extensive tests of this new approach for atomic clusters that are known to have energy landscapes for which conventional sampling schemes suffer from broken ergodicity. We also introduce a novel parallelization algorithm for nested sampling.

  18. Multistate nested canalizing functions

    CERN Document Server

    Adeyeye, J O; Laubenbacher, R; Li, Y

    2013-01-01

    The concept of a nested canalizing Boolean function has been studied over the course of the last decade in the context of understanding the regulatory logic of molecular interaction networks, such as gene regulatory networks. Such functions appear preferentially in published models of such networks. Recently, this concept has been generalized to include multi-state functions, and a recursive formula has been derived for their number, as a function of the number of variables. This paper carries out a detailed analysis of the class of nested canalizing functions over an arbitrary finite field. Furthermore, the paper generalizes the concept further, and derives a closed formula for the number of such generalized functions. The paper also derives a closed formula for the number of equivalence classes under permutation of variables. This is motivated by the fact that two nested canalizing functions that differ by a permutation of the variables share many important properties with each other. The paper contributes ...

  19. Serenbe Nest Cottages

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T.; Curtis, O.; Kim, E.; Roberts, S.; Stephenson, R.

    2012-12-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with Martin Dodson Builders and the Serenbe community on the construction of a new test home in the suburbs of Atlanta, GA in the mixed humid climate zone. The most recent subdivision within the Serenbe community, the Nest, will contain 15 small footprint cottage style homes, and Southface has selected Lot Nine, as the test home for this study. This Nest subdivision serves as a project showcase for both the builder partner and the Serenbe community as a whole. The planning and design incorporated into the Nest cottages will be implemented in each home within the subdivision. These homes addresses Building America Savings targets and serve as a basis of design for other homes Martin Dodson plans to build within the Serenbe community.

  20. Separation of Cells using a Fluidic MEMS Device and a Quantitative Analysis of Cell Movement

    Science.gov (United States)

    Isoda, Takaaki; Ishida, Yasuaki

    Fluidic micro electro mechanical system (fluidic MEMS) devices, composed of a micro pump, mixer, valve, reactor, sensor and an electric circuit on a chip, have been widely applied in biotechnology and medical analyses. This study describes the design and fabrication of a fluidic MEMS device that can separate living leukocyte cells from a single droplet of blood (blood sample was flowed into the gap (40μm) between the two substrates driven by the difference in surface tension of the two materials. Leukocyte cells were left adhered to the lower hydrophobic surface, whereas red corpuscles flowed toward the exit of the fluidic MEMS device. The separation rate of the red corpuscles has been achieved to 91 ± 9% in a unit area of 0.1 mm2. Further, the change in an area of a living leukocyte cell separated in the chip, was quantitatively analyzed. This study proposes a method for separating and measuring living cells in a fluidic MEMS device.

  1. Multi-cellular 3D human primary liver cell culture elevates metabolic activity under fluidic flow.

    Science.gov (United States)

    Esch, Mandy B; Prot, Jean-Matthieu; Wang, Ying I; Miller, Paula; Llamas-Vidales, Jose Ricardo; Naughton, Brian A; Applegate, Dawn R; Shuler, Michael L

    2015-05-21

    We have developed a low-cost liver cell culture device that creates fluidic flow over a 3D primary liver cell culture that consists of multiple liver cell types, including hepatocytes and non-parenchymal cells (fibroblasts, stellate cells, and Kupffer cells). We tested the performance of the cell culture under fluidic flow for 14 days, finding that hepatocytes produced albumin and urea at elevated levels compared to static cultures. Hepatocytes also responded with induction of P450 (CYP1A1 and CYP3A4) enzyme activity when challenged with P450 inducers, although we did not find significant differences between static and fluidic cultures. Non-parenchymal cells were similarly responsive, producing interleukin 8 (IL-8) when challenged with 10 μM bacterial lipoprotein (LPS). To create the fluidic flow in an inexpensive manner, we used a rocking platform that tilts the cell culture devices at angles between ±12°, resulting in a periodically changing hydrostatic pressure drop between reservoirs and the accompanying periodically changing fluidic flow (average flow rate of 650 μL min(-1), and a maximum shear stress of 0.64 dyne cm(-2)). The increase in metabolic activity is consistent with the hypothesis that, similar to unidirectional fluidic flow, primary liver cell cultures increase their metabolic activity in response to fluidic flow periodically changes direction. Since fluidic flow that changes direction periodically drastically changes the behavior of other cells types that are shear sensitive, our findings support the theory that the increase in hepatic metabolic activity associated with fluidic flow is either activated by mechanisms other than shear sensing (for example increased opportunities for gas and metabolite exchange), or that it follows a shear sensing mechanism that does not depend on the direction of shear. Our mode of device operation allows us to evaluate drugs under fluidic cell culture conditions and at low device manufacturing and operation

  2. Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

    Science.gov (United States)

    Ackerman, Joshua T.; Ringelman, Kevin M.; Eadie, J.M.

    2012-01-01

    When nest predation levels are very high or very low, the absolute range of observable nest success is constrained (a floor/ceiling effect), and it may be more difficult to detect density-dependent nest predation. Density-dependent nest predation may be more detectable in years with moderate predation rates, simply because there can be a greater absolute difference in nest success between sites. To test this, we replicated a predation experiment 10 years after the original study, using both natural and artificial nests, comparing a year when overall rates of nest predation were high (2000) to a year with moderate nest predation (2010). We found no evidence for density-dependent predation on artificial nests in either year, indicating that nest predation is not density-dependent at the spatial scale of our experimental replicates (1-ha patches). Using nearest-neighbor distances as a measure of nest dispersion, we also found little evidence for “dispersion-dependent” predation on artificial nests. However, when we tested for dispersion-dependent predation using natural nests, we found that nest survival increased with shorter nearest-neighbor distances, and that neighboring nests were more likely to share the same nest fate than non-adjacent nests. Thus, at small spatial scales, density-dependence appears to operate in the opposite direction as predicted: closer nearest neighbors are more likely to be successful. We suggest that local nest dispersion, rather than larger-scale measures of nest density per se, may play a more important role in density-dependent nest predation.

  3. Noise reduction in supersonic jets by nozzle fluidic inserts

    Science.gov (United States)

    Morris, Philip J.; McLaughlin, Dennis K.; Kuo, Ching-Wen

    2013-08-01

    Professor Philip Doak spent a very productive time as a consultant to the Lockheed-Georgia Company in the early 1970s. The focus of the overall research project was the prediction and reduction of noise from supersonic jets. Now, 40 years on, the present paper describes an innovative methodology and device for the reduction of supersonic jet noise. The goal is the development of a practical active noise reduction technique for low bypass ratio turbofan engines. This method introduces fluidic inserts installed in the divergent wall of a CD nozzle to replace hard-wall corrugation seals, which have been demonstrated to be effective by Seiner (2005) [1]. By altering the configuration and operating conditions of the fluidic inserts, active noise reduction for both mixing and shock noise has been obtained. Substantial noise reductions have been achieved for mixing noise in the maximum noise emission direction and in the forward arc for broadband shock-associated noise. To achieve these reductions (on the order of greater than 4 and 2 dB for the two main components respectively), practically achievable levels of injection mass flow rates have been used. The total injected mass flow rates are less than 4% of the core mass flow rate and the effective operating injection pressure ratio has been maintained at or below the same level as the nozzle pressure ratio of the core flow.

  4. Transport Phenomena of Water in Molecular Fluidic Channels

    Science.gov (United States)

    Vo, Truong Quoc; Kim, Bohung

    2016-09-01

    In molecular-level fluidic transport, where the discrete characteristics of a molecular system are not negligible (in contrast to a continuum description), the response of the molecular water system might still be similar to the continuum description if the time and ensemble averages satisfy the ergodic hypothesis and the scale of the average is enough to recover the classical thermodynamic properties. However, even in such cases, the continuum description breaks down on the material interfaces. In short, molecular-level liquid flows exhibit substantially different physics from classical fluid transport theories because of (i) the interface/surface force field, (ii) thermal/velocity slip, (iii) the discreteness of fluid molecules at the interface and (iv) local viscosity. Therefore, in this study, we present the result of our investigations using molecular dynamics (MD) simulations with continuum-based energy equations and check the validity and limitations of the continuum hypothesis. Our study shows that when the continuum description is subjected to the proper treatment of the interface effects via modified boundary conditions, the so-called continuum-based modified-analytical solutions, they can adequately predict nanoscale fluid transport phenomena. The findings in this work have broad effects in overcoming current limitations in modeling/predicting the fluid behaviors of molecular fluidic devices.

  5. Origami paper-based fluidic batteries for portable electrophoretic devices.

    Science.gov (United States)

    Chen, Sung-Sheng; Hu, Chih-Wei; Yu, I-Fan; Liao, Ying-Chih; Yang, Jing-Tang

    2014-06-21

    A manufacturing approach for paper-based fluidic batteries was developed based on the origami principle (three-dimension paper folding). Microfluidic channels were first created on a filter paper by a wax-printing method. Copper and aluminium sheets were then glued onto the paper as electrodes for the redox reaction. After the addition of copper sulphate and aluminium chloride, commonly available cellophane paper was attached as a membrane to separate the two electrodes. The resulting planar paper sheets were then folded into three-dimensional structures and compiled as a single battery with glue. The two half reactions (Al/Al(3+) and Cu/Cu(2+)) in the folded batteries provided an open-circuit potential from 0.82 V (one cell) to 5.0 V (eight cells in series) depending on the origami design. The prepared battery can provide a stable current of 500 μA and can light a regular LED for more than 65 min. These paper-based fluidic batteries in a set can also be compiled into a portable power bank to provide electric power for many electric or biomedical applications, such as LED lights and electrophoretic devices, as we report here.

  6. Bio-inspired fluidic lens surgical camera for MIS.

    Science.gov (United States)

    Tsai, Frank S; Johnson, Daniel; Cho, Sung Hwan; Qiao, Wen; Arianpour, Ashkan; Lo, Yu-Hwa

    2009-01-01

    We report a new type of surgical camera that will greatly improve minimally invasive surgery (MIS). The key enabling technology for this camera is a unique type of lens-bio-inspired fluidic lens, which is a bio-mimetic lens that can change its curvature, just like the way human crystalline lens can accommodate. Because of its curvature changing capability, it is now possible to design a new regime of optical systems where auto-focusing and optical zoom can be performed without moving the lens positions, as is done in typical cameras. Hence, miniaturized imaging system with high functionality can be achieved with such technology. MIS is a surgical technique where small incisions are made on the abdominal wall as opposed to a large cut in open surgery. This type of surgery ensures faster patient recovery. The key tool for MIS is its surgical camera, or laparoscope. Traditional laparoscope is long and rigid and limits the field of view. To further advance MIS technology, we utilized bio-inspired fluidic lens to design a highly versatile imager that is small, can change its field of view or zoom optically, works in low light conditions, and varies the viewing angles. The surgical camera prototype is small (total track<17 mm), possesses 3X optical zoom, operates with light emitting diode (LED) lighting, among many other unique features.

  7. Fluidic Force Discrimination Assays: A New Technology for Tetrodotoxin Detection

    Directory of Open Access Journals (Sweden)

    Cy R. Tamanaha

    2010-03-01

    Full Text Available Tetrodotoxin (TTX is a low molecular weight (~319 Da neurotoxin found in a number of animal species, including pufferfish. Protection from toxin tainted food stuffs requires rapid, sensitive, and specific diagnostic tests. An emerging technique for the detection of both proteins and nucleic acids is Fluidic Force Discrimination (FFD assays. This simple and rapid method typically uses a sandwich immunoassay format labeled with micrometer-diameter beads and has the novel capability of removing nonspecifically attached beads under controlled, fluidic conditions. This technique allows for near real-time, multiplexed analysis at levels of detection that exceed many of the conventional transduction methods (e.g., ELISAs. In addition, the large linear dynamic range afforded by FFD should decrease the need to perform multiple sample dilutions, a common challenge for food testing. By applying FFD assays to an inhibition immunoassay platform specific for TTX and transduction via low magnification microscopy, levels of detection of ~15 ng/mL and linear dynamic ranges of 4 to 5 orders of magnitude were achieved. The results from these studies on the first small molecule FFD assay, along with the impact to detection of seafood toxins, will be discussed in this manuscript.

  8. Fluidic Sampler. Tanks Focus Area. OST Reference No. 2007

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1999-09-01

    Problem Definition; Millions of gallons of radioactive and hazardous wastes are stored in underground tanks across the U.S. Department of Energy (DOE) complex. To manage this waste, tank operators need safe, cost-effective methods for mixing tank material, transferring tank waste between tanks, and collecting samples. Samples must be collected at different depths within storage tanks containing various kinds of waste including salt, sludge, and supernatant. With current or baseline methods, a grab sampler or a core sampler is inserted into the tank, waste is maneuvered into the sample chamber, and the sample is withdrawn from the tank. The mixing pumps in the tank, which are required to keep the contents homogeneous, must be shut down before and during sampling to prevent airborne releases. These methods are expensive, require substantial hands-on labor, increase the risk of worker exposure to radiation, and often produce nonrepresentative and unreproducible samples. How It Works: The Fluidic Sampler manufactured by AEA Technology Engineering Services, Inc., enables tank sampling to be done remotely with the mixing pumps in operation. Remote operation minimizes the risk of exposure to personnel and the possibility of spills, reducing associated costs. Sampling while the tank contents are being agitated yields consistently homogeneous, representative samples and facilitates more efficient feed preparation and evaluation of the tank contents. The above-tank portion of the Fluidic Sampler and the replacement plug and pipework that insert through the tank top are shown.

  9. Feathering Your Nest

    Science.gov (United States)

    Nabors, Martha L.; Edwards, Linda Carol; Decker, Suzanne

    2010-01-01

    The first-grade classroom was like a natural history museum. Bird nests of every shape and size lay on top of bookshelves that lined two walls. Methods students, who were visiting the classroom in preparation for the science lessons they would teach there, were immediately inspired by the collection. They used the collection as a springboard for…

  10. Application of fluidic lens technology to an adaptive holographic optical element see-through autophoropter

    Science.gov (United States)

    Chancy, Carl H.

    A device for performing an objective eye exam has been developed to automatically determine ophthalmic prescriptions. The closed loop fluidic auto-phoropter has been designed, modeled, fabricated and tested for the automatic measurement and correction of a patient's prescriptions. The adaptive phoropter is designed through the combination of a spherical-powered fluidic lens and two cylindrical fluidic lenses that are orientated 45o relative to each other. In addition, the system incorporates Shack-Hartmann wavefront sensing technology to identify the eye's wavefront error and corresponding prescription. Using the wavefront error information, the fluidic auto-phoropter nulls the eye's lower order wavefront error by applying the appropriate volumes to the fluidic lenses. The combination of the Shack-Hartmann wavefront sensor the fluidic auto-phoropter allows for the identification and control of spherical refractive error, as well as cylinder error and axis; thus, creating a truly automated refractometer and corrective system. The fluidic auto-phoropter is capable of correcting defocus error ranging from -20D to 20D and astigmatism from -10D to 10D. The transmissive see-through design allows for the observation of natural scenes through the system at varying object planes with no additional imaging optics in the patient's line of sight. In this research, two generations of the fluidic auto-phoropter are designed and tested; the first generation uses traditional glass optics for the measurement channel. The second generation of the fluidic auto-phoropter takes advantage of the progress in the development of holographic optical elements (HOEs) to replace all the traditional glass optics. The addition of the HOEs has enabled the development of a more compact, inexpensive and easily reproducible system without compromising its performance. Additionally, the fluidic lenses were tested during a National Aeronautics Space Administration (NASA) parabolic flight campaign, to

  11. Simulated nests in wildlife management

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Many of us have studied game bird nests. Usually we hoped to learn something about nesting cover, cover management and the birds and animals which seemed to eat the...

  12. Fabrication of PLGA nanoparticles with a fluidic nanoprecipitation system

    Directory of Open Access Journals (Sweden)

    Xie Hui

    2010-08-01

    Full Text Available Abstract Particle size is a key feature in determining performance of nanoparticles as drug carriers because it influences circulating half-life, cellular uptake and biodistribution. Because the size of particles has such a major impact on their performance, the uniformity of the particle population is also a significant factor. Particles comprised of the polymer poly(lactic-co-glycolic acid (PLGA are widely studied as therapeutic delivery vehicles because they are biodegradable and biocompatible. In fact, microparticles comprised of PLGA are already approved for drug delivery. Unfortunately, PLGA nanoparticles prepared by conventional methods usually lack uniformity. We developed a novel Fluidic NanoPrecipitation System (FNPS to fabricate highly uniform PLGA particles. Several parameters can be fine-tuned to generate particles of various sizes.

  13. Analysis of cantilever NEMS in centrifugal-fluidic systems

    Science.gov (United States)

    Mohsen-Nia, Mohsen; Abadian, Fateme; Abadian, Naeime; Dehkordi, Keivan Mosaiebi; Keivani, Maryam; Abadyan, Mohamadreza

    2016-07-01

    Electromechanical nanocantilevers are promising for using as sensors/detectors in centrifugal-fluidic systems. For this application, the presence of angular speed and electrolyte environment should be considered in the theoretical analysis. Herein, the pull-in instability of the nanocantilever incorporating the effects of angular velocity and liquid media is investigated using a size-dependent continuum theory. Using d’Alembert principle, the angular speed is transformed into an equivalent centrifugal force. The electrochemical and dispersion forces are incorporated considering the corrections due to the presence of electrolyte media. Two different approaches, i.e., the Rayleigh-Ritz method (RRM) and proposing a lumped parameter model (LPM), were applied to analyze the system. The models are validated with the results presented in literature. Impacts of the angular velocity, electrolyte media, dispersion forces, and size effect on the instability characteristics of the nanocantilever are discussed.

  14. Experimental Observation of Bohr's Nonlinear Fluidic Surface Oscillation

    CERN Document Server

    Moon, Songky; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2015-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of $0.41\\dot{6}\\eta^2$ for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of $\\eta$ much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained...

  15. Magnetohydrodynamic actuation of droplets for millimetric planar fluidic systems

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, A., E-mail: ali.ahmadi@ubc.ca; McDermid, C. M.; Markley, L. [School of Engineering, University of British Columbia, Kelowna, British Columbia V1V 1V7 (Canada)

    2016-01-04

    In this work, a magnetohydrodynamic method is proposed for the actuation of droplets in small-scale planar fluidic systems, providing an alternative to commonly used methods such as electrowetting-on-dielectric. Elementary droplet-based operations, including transport, merging, and mixing, are demonstrated. The forces acting on millimetric droplets are carefully investigated, with a primary focus on the magnetic actuation force and on the unbalanced capillary forces that arise due to hysteresis. A super-hydrophobic channel is 3D printed to guide the droplets, with thin wires installed as contact electrodes and permanent magnets providing a static magnetic field. It is shown that droplet motion is enhanced by increasing the droplet size and minimizing the electrode contact surface. The effects of channel geometry on threshold voltage and minimum moveable droplet volume are characterized. Finally, the presence of electrolysis is investigated and mitigating strategies are discussed.

  16. Quantum dot conjugates in a sub-micrometer fluidic channel

    Science.gov (United States)

    Stavis, Samuel M.; Edel, Joshua B.; Samiee, Kevan T.; Craighead, Harold G.

    2010-04-13

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  17. Design and fabrication of a micro fluidic circuit for the separation of micron sized particles

    CSIR Research Space (South Africa)

    Khumalo, F

    2009-07-01

    Full Text Available The development of a micro fluidic circuit for the separation of micro particles is being investigated. There are a wide range of available separation techniques such as acoustic, laminar flow, split flow, optical trapping and centrifugal forces...

  18. Nest and nest site characterisitcs of some ground-nesting, non-passerine birds of northern grasslands

    Science.gov (United States)

    Kantrud, H.A.; Higgins, K.F.

    1992-01-01

    We summarized biological and ecologic characteristics of 2490 nests of 16 species of upland-nesting, non-passerine birds of northern grasslands found during 1963 through 1991. Nest initiation and hatch dates, clutch sizes, nest fates, causes of failure, success rates of nests among major habitat types and land uses, and vegetation measurements at nest sites are analyzed.

  19. Rapid prototyping tools and methods for all-Topas (R) cyclic olefin copolymer fluidic microsystems

    DEFF Research Database (Denmark)

    Bundgaard, Frederik; Perozziello, Gerardo; Geschke, Oliver

    2006-01-01

    , good machinability, and good optical properties. A number of different processes for rapid and low-cost prototyping of all-Topas microfluidic systems, made with desktop machinery, are presented. Among the processes are micromilling of fluidic structures with a width down to 25 p,m and sealing...... of fluidic channels by thermal bonding or laser bonding, using a thin, spin-coated layer of carbon particles between the Topas substrate and the lid to absorb the laser light....

  20. A Comparison of Fluidic and Physical Obstacles for Deflagration-to-Detonation Transition

    Science.gov (United States)

    2010-12-16

    Bruun, H. H., Hot - Wire Anemometry , Oxford University Press, Oxford, 1995. 13. Naples, A., Yu, S.T.J., Hoke, J., Busby, K., Schauer, F., “Pressure...downstream of both obstacles with hot -film anemometry during non-reacting steady flow, show a conservative trend that a fluidic obstacle produces...downstream of both obstacles with hot -film anemometry during non-reacting steady flow, show a conservative trend that a fluidic obstacle produces

  1. Investigation of Combustion Control in a Dump Combustor Using the Feedback Free Fluidic Oscillator

    Science.gov (United States)

    Meier, Eric J.; Casiano, Matthew J.; Anderson, William E.; Heister, Stephen D.

    2015-01-01

    A feedback free fluidic oscillator was designed and integrated into a single element rocket combustor with the goal of suppressing longitudinal combustion instabilities. The fluidic oscillator uses internal fluid dynamics to create an unsteady outlet jet at a specific frequency. An array of nine fluidic oscillators was tested to mimic modulated secondary oxidizer injection into the combustor dump plane. The combustor has a coaxial injector that uses gaseous methane and decomposed hydrogen peroxide with an overall O/F ratio of 11.7. A sonic choke plate on an actuator arm allows for continuous adjustment of the oxidizer post acoustics enabling the study of a variety of instability magnitudes. The fluidic oscillator unsteady outlet jet performance is compared against equivalent steady jet injection and a baseline design with no secondary oxidizer injection. At the most unstable operating conditions, the unsteady outlet jet saw a 67% reduction in the instability pressure oscillation magnitude when compared to the steady jet and baseline data. Additionally, computational fluid dynamics analysis of the combustor gives insight into the flow field interaction of the fluidic oscillators. The results indicate that open loop high frequency propellant modulation for combustion control can be achieved through fluidic devices that require no moving parts or electrical power to operate.

  2. Intelligent nesting system

    Directory of Open Access Journals (Sweden)

    Đuričić Zoran

    2003-01-01

    Full Text Available The economy of the process for the manufacture of parts from sheet metal plates depends on successful solution of the process of cutting various parts from sheet metal plates. Essentially, the problem is to arrange contours within a defined space so that they take up minimal surface. When taken in this way, the considered problem assumes a more general nature; it refers to the utilization of a flat surface, and it can represent a general principle of arranging 2D contours on a certain surface. The paper presents a conceptual solution and a prototypal intelligent nesting system for optimal cutting. The problem of nesting can generally be divided into two intellectual phases: recognition and classification of shapes, and arrangement of recognized shapes on a given surface. In solving these problems, methods of artificial intelligence are applied. In the paper, trained neural network is used for recognition of shapes; on the basis of raster record of a part's drawing, it recognizes the part's shape and which class it belongs to. By means of the expert system, based on rules defined on the basis of acquisition of knowledge from manufacturing sections, as well as on the basis of certain mathematical algorithms, parts are arranged on the arrangement surface. Both systems can also work independently, having been built on the modular principle. The system uses various product models as elements of integration for the entire system. .

  3. PyNEST: a convenient interface to the NEST simulator

    Directory of Open Access Journals (Sweden)

    Jochen M Eppler

    2009-01-01

    Full Text Available The neural simulation tool NEST (http://www.nest-initiative.org is a simulator for heterogeneous networks of point neurons or neurons with a small number of compartments. It aims at simulations of large neural systems with more than 10^4 neurons and 10^7 to 10^9 synapses. NEST is implemented in C++ and can be used on a large range of architectures from single-core laptops over multi-core desktop computers to super-computers with thousands of processor cores. Python (http://www.python.org is a modern programming language that has recently received considerable attention in Computational Neuroscience. Python is easy to learn and has many extension modules for scientific computing (e.g. http://www.scipy.org. In this contribution we describe PyNEST, the new user interface to NEST. PyNEST combines NEST’s efficient simulation kernel with the simplicity and flexibility of Python. Compared to NEST’s native simulation language SLI, PyNEST makes it easier to set up simulations, generate stimuli, and analyze simulation results. We describe how PyNEST connects NEST and Python and how it is implemented. With a number of examples, we illustrate how it is used.

  4. Experimental Observation of Bohr’s Nonlinear Fluidic Surface Oscillation

    Science.gov (United States)

    Moon, Songky; Shin, Younghoon; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2016-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of 0.416η2 for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of η much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained a coefficient of 0.42 ± 0.08 consistently under various experimental conditions. We also measured the resonance mode spectrum of a two-dimensional cavity formed by the cross-sectional segment of the liquid jet. The observed spectra agree well with wave calculations assuming a coefficient of 0.414 ± 0.011. Our measurements establish the first experimental observation of Bohr’s hydrodynamic theory.

  5. Experimental Observation of Bohr's Nonlinear Fluidic Surface Oscillation.

    Science.gov (United States)

    Moon, Songky; Shin, Younghoon; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2016-01-25

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of 0.416η(2) for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of η much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained a coefficient of 0.42 ± 0.08 consistently under various experimental conditions. We also measured the resonance mode spectrum of a two-dimensional cavity formed by the cross-sectional segment of the liquid jet. The observed spectra agree well with wave calculations assuming a coefficient of 0.414 ± 0.011. Our measurements establish the first experimental observation of Bohr's hydrodynamic theory.

  6. Fluidic actuators for active flow control on airframe

    Science.gov (United States)

    Schueller, M.; Weigel, P.; Lipowski, M.; Meyer, M.; Schlösser, P.; Bauer, M.

    2016-04-01

    One objective of the European Projects AFLoNext and Clean Sky 2 is to apply Active Flow Control (AFC) on the airframe in critical aerodynamic areas such as the engine/wing junction or the outer wing region for being able to locally improve the aerodynamics in certain flight conditions. At the engine/wing junction, AFC is applied to alleviate or even eliminate flow separation at low speeds and high angle of attacks likely to be associated with the integration of underwing- mounted Ultra High Bypass Ratio (UHBR) engines and the necessary slat-cut-outs. At the outer wing region, AFC can be used to allow more aggressive future wing designs with improved performance. A relevant part of the work on AFC concepts for airframe application is the development of suitable actuators. Fluidic Actuated Flow Control (FAFC) has been introduced as a Flow Control Technology that influences the boundary layer by actively blowing air through slots or holes out of the aircraft skin. FAFC actuators can be classified by their Net Mass Flux and accordingly divided into ZNMF (Zero Net Mass Flux) and NZNMF (Non Zero Net-Mass-Flux) actuators. In the frame of both projects, both types of the FAFC actuator concepts are addressed. In this paper, the objectives of AFC on the airframe is presented and the actuators that are used within the project are discussed.

  7. Fluidic Control of Nozzle Flow: Some Performance Measurements

    Science.gov (United States)

    Federspiel, John; Bangert, Linda; Wing, David; Hawkes, Tim

    1995-01-01

    Results are presented of an experimental program that investigated the use of a secondary air stream to control the amount of flow through a convergent-divergent nozzle. These static tests utilized high pressure, ambient temperature air that was injected at the throat of the nozzle through an annular slot. Multiple injection slot sizes and injection angles were tested. The introduction of secondary flow was made in an opposing direction to the primary flow and the resulting flow field caused the primary stream to react as though the physical throat size had been reduced. The percentage reduction in primary flow rate was generally about twice the injected flow rate. The most effective throttling was achieved by injecting through the smallest slot in an orientation most nearly opposed to the approaching primary flow. Thrust edliciency, as measured by changes in nozzle thrust coefficient, was highest at high nozzle pressure ratios, NPR. The static test results agreed with predictions obtained prior from PABSD, a fully viscous computational fluid dynamics program. Since use of such an injection system on gas turbine engine exhaust nozzles would be primarily at high NPRs, it was concluded that fluidic control holds promise for reducing nozzle weight and complexity on future systems.

  8. Study of drilling muds on the anti-erosion property of a fluidic amplifier in directional drilling

    Directory of Open Access Journals (Sweden)

    Jiang-fu He

    2015-10-01

    Full Text Available Due to some drawbacks of conventional drilling methods and drilling tools, the application of hydraulic hammers with a fluidic amplifier have been extensively popularized since its emergence in recent years. However, the performance life of a fluidic amplifier is still unsatisfactory in oil and gas wells drilling, especially the heavy wear or erosion of the fluidic amplifier leads to the reduction of service life time of hydraulic hammers, which is derived from the incision of drilling muds with high speed and pressure. In order to investigate the influence of drilling muds, such as particle size, solid content and jet velocity, on the antierosion property of a fluidic amplifier, several groups of drilling muds with different performance parameters have been utilized to numerical simulation on basis of Computational Fluid Dynamics (CFD. Simulation results have shown that the jet nozzle of fluidic amplifiers is primarily abraded, afterwards are the lateral plates and the wedge of the fluidic amplifier, which shows extraordinary agreement with the actual cases of fluidic amplifier in drilling process. It can be concluded that particle size, solid content and jet velocity have a great influence on the anti-erosion property of a fluidic amplifier, and the erosion rate linearly varies with the particle size of drilling muds, nevertheless exponentially varies with solid content and jet velocity of drilling muds. As to improve the service life time of a fluidic amplifier, the mud purification system or low solid clay-free mud system is suggested in the operation of directional well drilling

  9. Impact of low versus high fluidic settings on the efficacy and safety of phacoemulsification.

    Science.gov (United States)

    Schriefl, Sabine M; Stifter, Eva; Menapace, Rupert

    2014-09-01

      To compare intraoperative efficiency and postoperative outcomes of cataract surgery with low and high fluidic settings.   In this prospective, randomized, single-blinded study, 114 eyes of 57 patients were operated with low fluidic settings for one eye (group I) and high fluidic settings for the other eye (group II). Efficiency was judged as metred surgery time, effective phacoemulsification time (EPT) and the amount of balanced salt solution used. Visual outcome and endothelial cell count were determined 1 week and 18 months postoperatively.   The overall effective phacoemulsification energy was statistically significantly lower (p = 0.003) in group II than in group I. Conquest of the nuclei was achieved with about two-thirds of the energy needed in group I, with 6.59 ± 4.79 effective ultrasound energy compared with 3.99 ± 3.18 (p = 0.001). Overall, about 12% more solution was used in group II than in group I. Median visual acuity was 1.0 for both groups 18 months after surgery. The mean endothelial cell loss was 5.0% in eyes in group I compared with 6.3% in eyes in group II (p > 0.5).   Switching from low fluidic settings with a conventional coaxial 20G phacoemulsification tip to higher fluidic settings with a microcoaxial phaco tip statistically significantly decreases EPT. As only marginally more solution was used with the higher aspiration flow, occlusion must be accomplished more often with high than with low fluidics. Aspiration of the quadrants was therefore more efficient with high fluidic settings. The enhanced pump speed did not result in more tissue damage. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. The Nest Home

    Energy Technology Data Exchange (ETDEWEB)

    Pickerill, Heath [Missouri Univ. of Science and Technology, Rolla, MO (United States)

    2016-07-11

    The purpose of the project was to build a competitive solar-powered house for the U.S. Department of Energy Solar Decathlon 2015 held in Irvine, California. The house, named the Nest Home, was an innovative design that works with the environment to meet the needs of the occupants, identified as a growing family. Reused materials were instrumental in the design. Three refurbished shipping containers composed the primary structure of the house, creating an open floor plan that defies common architecture for container homes. The exterior siding was made of deconstructed shipping pallets collected locally. Other recycled products included carpet composed of discarded fishing nets, denim batting made of recycled blue jeans that outperform traditional fiberglass insulation in sound proofing and thermal resistance, and kitchen cabinets that were purchased used and refinished. Collectively these elements formed a well-balanced blend of modern design, comfort, and sustainability. The house was Missouri University of Science and Technology’s sixth entry in the DOE Solar Decathlon. Missouri S&T has been invited to compete in six of the seven decathlons held, more than any other university worldwide. The house was brought back to Rolla after the Decathlon in California where it has been placed in its permanent location on the S&T campus.

  11. A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures

    Directory of Open Access Journals (Sweden)

    Tsud Nataliya

    2008-02-01

    Full Text Available Abstract Background Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction. Results We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend. Conclusion We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.

  12. Bacterial adhesion force quantification by fluidic force microscopy

    Science.gov (United States)

    Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A.

    2015-02-01

    Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology.Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many

  13. Geometrical optimisation of a biochip microchannel fluidic separator.

    Science.gov (United States)

    Xue, Xiangdong; Patel, Mayur K; Bailey, Chris; Desmulliez, Marc P Y

    2012-01-01

    This article reports on the geometric optimisation of a T-shaped biochip microchannel fluidic separator aiming to maximise the separation efficiency of plasma from blood through the improvement of the unbalanced separation performance among different channel bifurcations. For this purpose, an algebraic analysis is firstly implemented to identify the key parameters affecting fluid separation. A numerical optimisation is then carried out to search the key parameters for improved separation performance of the biochip. Three parameters, the interval length between bifurcations, the main channel length from the outlet to the bifurcation region and the side channel geometry, are identified as the key characteristic sizes and defined as optimisation variables. A balanced flow rate ratio between the main and side channels, which is an indication of separation effectiveness, is defined as the objective. It is found that the degradation of the separation performance is caused by the unbalanced channel resistance ratio between the main and side channel routes from bifurcations to outlets. The effects of the three key parameters can be summarised as follows: (a) shortening the interval length between bifurcations moderately reduces the differences in the flow rate ratios; (b) extending the length of the main channel from the main outlet is effective for achieving a uniformity of flow rate ratio but ineffective in changing the velocity difference of the side channels and (c) decreasing the lengths of side channels from upstream to downstream is effective for both obtaining a uniform flow rate ratio and reducing the differences in the flow velocities between the side branch channels. An optimisation process combining the three parameters is suggested as this integration approach leads to fast convergent process and also offers flexible design options for satisfying different requirements.

  14. Experimental investigation of the noise reduction of supersonic exhaust jets with fluidic inserts

    Science.gov (United States)

    Powers, Russell William Walter

    The noise produced by the supersonic, high temperature jets that exhaust from military aircraft is becoming a hazard to naval personnel and a disturbance to communities near military bases. Methods to reduce the noise produced from these jets in a practical full-scale environment are difficult. The development and analysis of distributed nozzle blowing for the reduction of radiated noise from supersonic jets is described. Model scale experiments of jets that simulate the exhaust jets from typical low-bypass ratio military jet aircraft engines during takeoff are performed. Fluidic inserts are created that use distributed blowing in the divergent section of the nozzle to simulate mechanical, hardwall corrugations, while having the advantage of being an active control method. This research focuses on model scale experiments to better understand the fluidic insert noise reduction method. Distributed blowing within the divergent section of the military-style convergent divergent nozzle alters the shock structure of the jet in addition to creating streamwise vorticity for the reduction of mixing noise. Enhancements to the fluidic insert design have been performed along with experiments over a large number of injection parameters and core jet conditions. Primarily military-style round nozzles have been used, with preliminary measurements of hardwall corrugations and fluidic inserts in rectangular nozzle geometries also performed. It has been shown that the noise reduction of the fluidic inserts is most heavily dependent upon the momentum flux ratio between the injector and core jet. Maximum reductions of approximately 5.5 dB OASPL have been observed with practical mass flow rates and injection pressures. The first measurements with fluidic inserts in the presence of a forward flight stream have been performed. Optimal noise reduction occurs at similar injector parameters in the presence of forward flight. Fluidic inserts in the presence of a forward flight stream were

  15. Determining DfT Hardware by VHDL-AMS Fault Simulation for Biological Micro-Electronic Fluidic Arrays

    NARCIS (Netherlands)

    Kerkhoff, H.G.; Zhang, X.; Liu, H.; Richardson, A.; Nouet, P.; Azais, F.

    2005-01-01

    The interest of microelectronic fluidic arrays for biomedical applications, like DNA determination, is rapidly increasing. In order to evaluate these systems in terms of required Design-for-Test structures, fault simulations in both fluidic and electronic domains are necessary. VHDL-AMS can be used

  16. Algebraic and numerical analysis of imaging properties of thin tunable-focus fluidic membrane lenses with parabolic surfaces.

    Science.gov (United States)

    Miks, Antonin; Novak, Jiri; Novak, Pavel

    2013-04-01

    The theory of third-order aberrations for a system of rotationally symmetric thin tunable-focus fluidic membrane lenses with parabolic surfaces is described. A complex analysis of the third-order design of tunable fluidic lenses is performed considering all types of primary aberrations. Moreover, formulas are derived for the calculation of the change of aberration coefficients of the parabolic tunable fluidic membrane lens with respect to the wavelength. It is shown that spherical aberration of a simple tunable-focus fluidic membrane lens with parabolic surfaces can be corrected, which is not possible with a classical spherical lens. The presented analysis is explained on examples. Derived formulas make possible to calculate parameters of optical systems with fluidic membrane lenses with small residual aberrations.

  17. Tunable sound transmission at an impedance-mismatched fluidic interface assisted by a composite waveguide

    Science.gov (United States)

    Zhang, Hui; Wei, Zhi; Fan, Li; Qu, Jianmin; Zhang, Shu-Yi

    2016-10-01

    We report a composite waveguide fabricated by attaching a coupling aperture to a waveguide. The acoustic impedance of the composite waveguide can be regulated by merely controlling its coupling vibrations, depending on its structure size. By changing the size to adjust the acoustic impedance of the composite waveguide at an impedance-mismatched fluidic interface, tunable sound transmission at the desired frequencies is achieved. The reported composite waveguide provides a new method for sound regulation at a mismatched fluidic interface and has extensive frequency hopping and frequency agility applications in air-water sound communication.

  18. Nested subgraphs of complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Corominas-Murtra, Bernat; Sole, Ricard V [ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Dr Aiguader 80, 08003 Barcelona (Spain); Mendes, Jose F F [Departamento de Fisica da Universidade de Aveiro, 3810-193 Aveiro (Portugal)], E-mail: bernat.corominas@upf.edu

    2008-09-26

    We analytically explore the scaling properties of a general class of nested subgraphs in complex networks, which includes the K-core and the K-scaffold, among others. We name such a class of subgraphs K-nested subgraphs since they generate families of subgraphs such that ...S{sub K+1}(G) subset or equal S{sub K}(G) subset or equal S{sub K-1}(G).... Using the so-called configuration model it is shown that any family of nested subgraphs over a network with diverging second moment and finite first moment has infinite elements (i.e. lacking a percolation threshold). Moreover, for a scale-free network with the above properties, we show that any nested family of subgraphs is self-similar by looking at the degree distribution. Both numerical simulations and real data are analyzed and display good agreement with our theoretical predictions.

  19. Investigation of combustion control in a dump combustor using the feedback free fluidic oscillator

    Science.gov (United States)

    Meier, Eric J.

    The feedback free fluidic oscillator uses the unsteady nature of two colliding jets to create a single oscillating outlet jet with a wide sweep angle. These devices have the potential to provide additional combustion control, boundary layer control, thrust vectoring, and industrial flow deflection. Two-dimensional computational fluid dynamics, CFD, was used to analyze the jet oscillation frequency over a range of operating conditions and to determine the effect that geometric changes in the oscillator design have on the frequency. Results presented illustrate the changes in jet oscillation frequency with gas type, gas temperature, operating pressure, pressure ratio across the oscillator, aspect ratio of the oscillator, and the frequency trends with various changes to the oscillator geometry. A fluidic oscillator was designed and integrated into single element rocket combustor with the goal of suppressing longitudinal combustion instabilities. An array of nine fluidic oscillators was tested to mimic modulated secondary oxidizer injection into the dump plane using 15% of the oxidizer flow. The combustor has a coaxial injector that uses gaseous methane and decomposed hydrogen peroxide at an O/F of 11.66. A sonic choke plate on an actuator arm allows for continuous adjustment of the oxidizer post acoustics for studying a variety of instability magnitudes. The fluidic oscillator unsteady outlet jet performance is compared with equivalent steady jet injection and a baseline design with no secondary oxidizer injection. At the most unstable operating conditions, the unsteady outlet jet saw a 60% reduction in the instability pressure oscillation magnitude when compared to the steady jet and baseline data. The results indicate open loop propellant modulation for combustion control can be achieved through fluidic devices that require no moving parts or electrical power to operate. Three-dimensional computational fluid dynamics, 3-D CFD, was conducted to determine the

  20. Factors influencing depredation of artificial duck nests

    Science.gov (United States)

    Esler, Daniel N.; Grand, James B.

    1993-01-01

    Because artificial nests can facilitate controlled experiments of nest success, we used them to assess whether human visitation, nest density, vegetation structure, and proximity to habitat edge could affect depredation of duck nests on Yukon Flats National Wildlife Refuge, Alaska. More (P depredated than those in plots visited at intervals of 7 (40%), 14 (35%), or 28 days (45%). More (P depredated in a plot with 10 nests/ha (95%) than nests in a plot of a lower density (2/ha; 40%). Vegetation height, vegetation density, distance to a wetland, distance to forest edge, or distance to the nearest ecotone did not differ (P > 0.05) between depredated and undisturbed nests. We suggest that daily visitation of duck nests increases depredation, but longer intervals, typical of most nest studies, do not. High nesting densities, which could occur when flooding limits nesting habitat, may result in higher depredation rates.

  1. Nest poaching in Neotropical parrots

    Science.gov (United States)

    Wright, T.F.; Toft, C.A.; Enkerlin-Hoeflich, E.; Gonzalez-Elizondo, J.; Albornoz, M.; Rodriguez-Ferraro, A.; Rojas-Suarez, F.; Sanz, V.; Trujillo, A.; Beissinger, S.R.; Berovides A., V.; Galvez A., X.; Brice, A.T.; Joyner, K.; Eberhard, J.; Gilardi, J.; Koenig, S.E.; Stoleson, S.; Martuscelli, P.; Meyers, J.M.; Renton, K.; Rodriguez, A.M.; Sosa-Asanza, A.C.; Vilella, F.J.; Wiley, J.W.

    2001-01-01

    Although the poaching of nestlings for the pet trade is thought to contribute to the decline of many species of parrots, its effects have been poorly demonstrated. We calculated rates of mortality due to nest poaching in 23 studies of Neotropical parrots, representing 4024 nesting attempts in 21 species and 14 countries. We also examined how poaching rates vary with geographic region, presence of active protection programs, conservation status and economic value of a species, and passage of the U.S. Wild Bird Conservation Act. The average poaching rate across all studies was 30% of all nests observed. Thirteen studies reported poaching rates of >20%, and four reported rates of >70%. Only six studies documented no nest poaching. Of these, four were conducted on islands in the Caribbean region, which had significantly lower poaching rates than the mainland Neotropics. The other two studies that showed no poaching were conducted on the two species with the lowest economic value in our sample (U.S. retail price). In four studies that allowed direct comparison between poaching at sites with active nest protection versus that at unprotected sites, poaching rates were significantly lower at protected sites, suggesting that active protection efforts can be effective in reducing nest poaching. In those studies conducted both before and after the passage of the U.S. Wild Bird Conservation Act, poaching rates were found to be significantly lower following its enactment than in the period before. This result supports the hypothesis that the legal and illegal parrot trades are positively related, rather than inversely related as has been suggested by avicultural interests. Overall, our study indicates that poaching of parrot nestlings for economic gain is a widespread and biologically significant source of nest mortality in Neotropical parrots.

  2. Nano-inspired smart interfaces: fluidic interactivity and its impact on heat transfer

    Science.gov (United States)

    Kim, Beom Seok; Lee, Byoung In; Lee, Namkyu; Choi, Geehong; Gemming, Thomas; Cho, Hyung Hee

    2017-01-01

    Interface-inspired convection is a key heat transfer scheme for hot spot cooling and thermal energy transfer. An unavoidable trade-off of the convective heat transfer is pressure loss caused by fluidic resistance on an interface. To overcome this limitation, we uncover that nano-inspired interfaces can trigger a peculiar fluidic interactivity, which can pursue all the two sides of the coin: heat transfer and fluidic friction. We demonstrate the validity of a quasi-fin effect of Si-based nanostructures based on conductive capability of heat dissipation valid under the interactivity with fluidic viscous sublayer. The exclusive fluid-interface friction is achieved when the height of the nanostructures is much less than the thickness of the viscous sublayers in the turbulent regime. The strategic nanostructures show an enhancement of heat transfer coefficients in the wall jet region by more than 21% without any significant macroscale pressure loss under single-phase impinging jet. Nanostructures guaranteeing fluid access via an equivalent vacancy larger than the diffusive path length of viscid flow lead to local heat transfer enhancement of more than 13% at a stagnation point. Functional nanostructures will give shape to possible breakthroughs in heat transfer and its optimization can be pursued for engineered systems. PMID:28345613

  3. Fluidic origami: a plant-inspired adaptive structure with shape morphing and stiffness tuning

    Science.gov (United States)

    Li, Suyi; Wang, K. W.

    2015-10-01

    Inspired by the physics behind the rapid plant movements and the rich topologies in origami folding, this research creates a unique class of multi-functional adaptive structure through exploring the innovation of fluidic origami. The idea is to connect multiple Miura folded sheets along their crease lines into a space-filling structure, and fill the tubular cells in-between with working fluids. The pressure and fluid flow in these cells can be strategically controlled much like in plants for nastic movements. The relationship between the internal fluid volume and the overall structure deformation is primarily determined by the kinematics of folding. This relationship can be exploited so that fluidic origami can achieve actuation/morphing by actively changing the internal fluid volume, and stiffness tuning by constraining the fluid volume. In order to characterize the working principles and performance potentials of these two adaptive functions, this research develops an equivalent truss frame model on a fluidic origami unit cell to analyze its fundamental elastic characteristics. Eigen-stiffness analysis based on this model reveals the primary modes of deformation and their relationships with initial folding configurations. Performances of the adaptive functions are correlated to the crease pattern design. In parallel to analytical studies, the feasibility of the morphing and stiffness tuning is also examined experimentally via a 3D printed multi-material prototype demonstrator. The research reported in this paper could lead to the synthesis of adaptive fluidic origami cellular metastructures or metamaterial systems for various engineering applications.

  4. Fluidic origami with embedded pressure dependent multi-stability: a plant inspired innovation.

    Science.gov (United States)

    Li, Suyi; Wang, K W

    2015-10-06

    Inspired by the impulsive movements in plants, this research investigates the physics of a novel fluidic origami concept for its pressure-dependent multi-stability. In this innovation, fluid-filled tubular cells are synthesized by integrating different Miura-Ori sheets into a three-dimensional topological system, where the internal pressures are strategically controlled similar to the motor cells in plants. Fluidic origami incorporates two crucial physiological features observed in nature: one is distributed, pressurized cellular organization, and the other is embedded multi-stability. For a single fluidic origami cell, two stable folding configurations can coexist due to the nonlinear relationships among folding, crease material deformation and internal volume change. When multiple origami cells are integrated, additional multi-stability characteristics could occur via the interactions between pressurized cells. Changes in the fluid pressure can tailor the existence and shapes of these stable folding configurations. As a result, fluidic origami can switch between being mono-stable, bistable and multi-stable with pressure control, and provide a rapid 'snap-through' type of shape change based on the similar principles as in plants. The outcomes of this research could lead to the development of new adaptive materials or structures, and provide insights for future plant physiology studies at the cellular level.

  5. Characterizing Laminar Flame Interactions with Turbulent Fluidic Jets and Solid Obstacles for Turbulence Induction

    Science.gov (United States)

    Gerdts, Stephen; Chambers, Jessica; Ahmed, Kareem

    2016-11-01

    A detonation engine's fundamental design concept focuses on enhancing the Deflagration to Detonation Transition (DDT), the process through which subsonic flames accelerate to form a spontaneous detonation wave. Flame acceleration is driven by turbulent interactions that expand the reaction zone and induce mixing of products and reactants. Turbulence in a duct can be generated using solid obstructions, fluidic obstacles, duct angle changes, and wall skin friction. Solid obstacles have been previously explored and offer repeatable turbulence induction at the cost of pressure losses and additional system weight. Fluidic jet obstacles are a novel technique that provide advantages such as the ability to be throttled, allowing for active control of combustion modes. The scope of the present work is to expand the experimental database of varying parameters such as main flow and jet equivalence ratios, fluidic momentum ratios, and solid obstacle blockage ratios. Schlieren flow visualization and particle image velocimetry (PIV) are employed to investigate turbulent flame dynamics throughout the interaction. Optimum conditions that lead to flame acceleration for both solid and fluidic obstacles will be determined. American Chemical Society.

  6. Customizable 3D Printed 'Plug and Play' Millifluidic Devices for Programmable Fluidics.

    Directory of Open Access Journals (Sweden)

    Soichiro Tsuda

    Full Text Available Three dimensional (3D printing is actively sought after in recent years as a promising novel technology to construct complex objects, which scope spans from nano- to over millimeter scale. Previously we utilized Fused deposition modeling (FDM-based 3D printer to construct complex 3D chemical fluidic systems, and here we demonstrate the construction of 3D milli-fluidic structures for programmable liquid handling and control of biological samples. Basic fluidic operation devices, such as water-in-oil (W/O droplet generators for producing compartmentalized mono-disperse droplets, sensor-integrated chamber for online monitoring of cellular growth, are presented. In addition, chemical surface treatment techniques are used to construct valve-based flow selector for liquid flow control and inter-connectable modular devices for networking fluidic parts. As such this work paves the way for complex operations, such as mixing, flow control, and monitoring of reaction / cell culture progress can be carried out by constructing both passive and active components in 3D printed structures, which designs can be shared online so that anyone with 3D printers can reproduce them by themselves.

  7. Low voltage electroosmotic pump for high density integration into microfabricated fluidic systems

    NARCIS (Netherlands)

    Heuck, F.C.A.; Staufer, U.

    2011-01-01

    A low voltage electroosmotic (eo) pump suitable for high density integration into microfabricated fluidic systems has been developed. The high density integration of the eo pump required a small footprint as well as a specific on-chip design to ventilate the electrolyzed gases emerging at the platin

  8. A Computational Study of a New Dual Throat Fluidic Thrust Vectoring Nozzle Concept

    Science.gov (United States)

    Deere, Karen A.; Berrier, Bobby L.; Flamm, Jeffrey D.; Johnson, Stuart K.

    2005-01-01

    A computational investigation of a two-dimensional nozzle was completed to assess the use of fluidic injection to manipulate flow separation and cause thrust vectoring of the primary jet thrust. The nozzle was designed with a recessed cavity to enhance the throat shifting method of fluidic thrust vectoring. Several design cycles with the structured-grid, computational fluid dynamics code PAB3D and with experiments in the NASA Langley Research Center Jet Exit Test Facility have been completed to guide the nozzle design and analyze performance. This paper presents computational results on potential design improvements for best experimental configuration tested to date. Nozzle design variables included cavity divergence angle, cavity convergence angle and upstream throat height. Pulsed fluidic injection was also investigated for its ability to decrease mass flow requirements. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 2 to 7, with the fluidic injection flow rate equal to 3 percent of the primary flow rate. Computational results indicate that increasing cavity divergence angle beyond 10 is detrimental to thrust vectoring efficiency, while increasing cavity convergence angle from 20 to 30 improves thrust vectoring efficiency at nozzle pressure ratios greater than 2, albeit at the expense of discharge coefficient. Pulsed injection was no more efficient than steady injection for the Dual Throat Nozzle concept.

  9. Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

    Directory of Open Access Journals (Sweden)

    Myeong-Woo Cho

    2007-08-01

    Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip, has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

  10. Development of fluidic device in SIT for Korean Next Generation Reactor I

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Bong Hyun; Lee, Joon; Bae, Yoon Young; Park, Jong Kyun

    1999-07-01

    The KNGR is to install a Fluidic Device at the bottom of the inner space of the SIT (Safety Injection Tank) to control the flow rate of safety injection coolant from SIT during LBLOCA. During the past two years, a scale model test to obtain the required flow characteristics of the device under the KNGR specific conditions has been performed using the experience and existing facility of AEA Technology (UK) with appropriate modifications. The performance verification test is to be performed this year to obtain optimum characteristics and design data of full size fluidic device. The purpose of the model test was to check the feasibility of developing the device and to produce a generic flow characteristic data. The test was performed in approximately 1/7 scale in terms of flow rate with full height and pressure. This report presents the details ofsystem performance requirements for the device, design procedure for the fluidic device to be used, test facility and test method. The time dependent flow, pressure and Euler number are presented as characteristics curves and the most stable and the most effective flow control characteristic parameters were recommended through the evaluation. A method to predict the size of the fluidic device is presented. And a sizing algorithm, which can be used to conveniently determine the major geometric data of the device for various operating conditions, and a FORTRAN program to produce the prediction of performance curves have been developed. (author). 32 refs., 15 tabs., 47 figs.

  11. A capability study of micro moulding for nano fluidic system manufacture

    DEFF Research Database (Denmark)

    Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

    2013-01-01

    With the present paper the authors analysed process capability of ultra-precision moulding used for producing nano crosses with the same critical channels dimensions of a nano fluidic system for optical mapping of genomic length DNA. The process variation focused on product tolerances is quantified...

  12. Vibration interference analysis and verification of micro-fluidic inertial switch

    Directory of Open Access Journals (Sweden)

    Liu Tingting

    2014-02-01

    Full Text Available The micro-fluidic inertial switch based on liquid metal utilizes the moving mercury droplet to close the switch under the action of acceleration, which is characterized by no moving parts, small contact resistance, long service life and large current. In addition to the requirement of response time, accuracy and reliability, the micro-fluidic inertial switch needs to overcome the impact of the ambient vibration. The influence of the ambient vibration on the performance of switch is investigated by loading pulse or sinusoidal interference signals in the X, Y and Z direction. The numerical results suggest that the performance of micro-fluidic inertial switch is greatly affected by impact interference signal in X sensitive direction as compared with low frequency harmonic signal. If the impact signal with high amplitude lasts only for a short time, the wrong operation might also occur. The interference signals in insensitive direction have a relatively small impact on the performance of switch, and the impact of interference signal can be reduced by reasonable structural design. Finally, anodic bonding, deep reactive ion etching (DRIE and sputtering technique are adopted to fabricate the micro-fluidic inertial switch. The acceleration threshold of the prototype is tested. The experiment results agree with the numerical results, which indicate that the simulation method is valid.

  13. Vibration interference analysis and verification of micro-fluidic inertial switch

    Science.gov (United States)

    Tingting, Liu; Wei, Su; Tao, Yang; Yuan, Xu

    2014-03-01

    The micro-fluidic inertial switch based on liquid metal utilizes the moving mercury droplet to close the switch under the action of acceleration, which is characterized by no moving parts, small contact resistance, long service life and large current. In addition to the requirement of response time, accuracy and reliability, the micro-fluidic inertial switch needs to overcome the impact of the ambient vibration. The influence of the ambient vibration on the performance of switch is investigated by loading pulse or sinusoidal interference signals in the X, Y and Z direction. The numerical results suggest that the performance of micro-fluidic inertial switch is greatly affected by impact interference signal in X sensitive direction as compared with low frequency harmonic signal. If the impact signal with high amplitude lasts only for a short time, the wrong operation might also occur. The interference signals in insensitive direction have a relatively small impact on the performance of switch, and the impact of interference signal can be reduced by reasonable structural design. Finally, anodic bonding, deep reactive ion etching (DRIE) and sputtering technique are adopted to fabricate the micro-fluidic inertial switch. The acceleration threshold of the prototype is tested. The experiment results agree with the numerical results, which indicate that the simulation method is valid.

  14. Fluidic origami with embedded pressure dependent multi-stability: a plant inspired innovation

    Science.gov (United States)

    Li, Suyi; Wang, K. W.

    2015-01-01

    Inspired by the impulsive movements in plants, this research investigates the physics of a novel fluidic origami concept for its pressure-dependent multi-stability. In this innovation, fluid-filled tubular cells are synthesized by integrating different Miura-Ori sheets into a three-dimensional topological system, where the internal pressures are strategically controlled similar to the motor cells in plants. Fluidic origami incorporates two crucial physiological features observed in nature: one is distributed, pressurized cellular organization, and the other is embedded multi-stability. For a single fluidic origami cell, two stable folding configurations can coexist due to the nonlinear relationships among folding, crease material deformation and internal volume change. When multiple origami cells are integrated, additional multi-stability characteristics could occur via the interactions between pressurized cells. Changes in the fluid pressure can tailor the existence and shapes of these stable folding configurations. As a result, fluidic origami can switch between being mono-stable, bistable and multi-stable with pressure control, and provide a rapid ‘snap-through’ type of shape change based on the similar principles as in plants. The outcomes of this research could lead to the development of new adaptive materials or structures, and provide insights for future plant physiology studies at the cellular level. PMID:26400197

  15. Reflow bonding of borosilicate glass tubes to silicon substrates as fluidic interconnects

    NARCIS (Netherlands)

    Mogulkoc, Berker

    2010-01-01

    The subject of the thesis was the use of borosilicate glass tubes as an interface to waferlevel microfluidic devices. The tubes are compatible with the standard fluidic connectors and can be used as a package for the so-called MEMS-on-a-tube assembly. The connections are produced by the brief reflow

  16. Flexible fluidic microchips based on thermoformed and locally modified thin polymer films

    NARCIS (Netherlands)

    Truckenmüller, R.; Giselbrecht, S.; Blitterswijk, van C.; Dambrowsky, N.; Gottwald, E.; Mappes, T.; Rolletschek, A.; Saile, V.; Trautmann, C.; Weibezahn, K.-F.; Welle, A.

    2008-01-01

    This paper presents a fundamentally new approach for the manufacturing and the possible applications of lab on a chip devices, mainly in the form of disposable fluidic microchips for life sciences applications. The new technology approach is based on a novel microscale thermoforming of thin polymer

  17. Fluidic system for long-term in vitro culturing and monitoring of organotypic brain slices

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Troels-Smith, Ane R.; Dimaki, Maria

    2015-01-01

    Brain slice preparations cultured in vitro have long been used as a simplified model for studying brain development, electrophysiology, neurodegeneration and neuroprotection. In this paper an open fluidic system developed for improved long term culturing of organotypic brain slices is presented. ...

  18. Optimal Control of Airfoil Flow Separation using Fluidic Excitation

    Science.gov (United States)

    Shahrabi, Arireza F.

    This thesis deals with the control of flow separation around a symmetric airfoils with the aid of multiple synthetic jet actuators (SJAs). CFD simulation methods have been implemented to uncover the flow separation regimes and associated properties such as frequencies and momentum ratio. In the first part of the study, the SJA was studied thoroughly. Large Eddy Simulations (LES) were performed for one individual cavity; the time history of SJA of the outlet velocity profile and the net momentum imparted to the flow were analyzed. The studied SJA is asymmetrical and operates with the aid of a piezoelectric (PZT) ceramic circular plate actuator. A three-dimensional mesh for the computational domain of the SJA and the surrounding volume was developed and was used to evaluate the details of the airflow conditions inside the SJA as well as at the outlet. The vibration of the PZT ceramic actuator was used as a boundary condition in the computational model to drive the SJA. Particular attention was given to developing a predictive model of the SJA outlet velocity. Results showed that the SJA velocity output is correlated to the PZT ceramic plate vibration, especially for the first frequency mode. SJAs are a particular class of zero net mass flux (ZNMF) fluidic devices with net imparted momentum to the flow. The net momentum imparted to the flow in the separated region is such that positive enhancement during AFC operations is achieved. Flows around the NACA 0015 airfoil were simulated for a range of operating conditions. Attention was given to the active open and closed loop control solutions for an airfoil with SJA at different angles of attack and flap angles. A large number of simulations using RANS & LES models were performed to study the effects of the momentum ratio (Cμ) in the range of 0 to 11% and of the non-dimensional frequency, F+, in the range of 0 to 2 for the control of flow separation at a practical angle of attack and flap angle. The optimum value of C

  19. Successful nesting behavior of Puerto Rican parrots

    Science.gov (United States)

    Wilson, K.A.; Field, R.; Wilson, M.H.

    1995-01-01

    We analyzed nesting behavior of five pairs of the endangered Puerto Rican Parrot (Amazona vittata) during eight successful nesting attempts. Each stage of the nesting cycle (egg laying, incubation, early chick rearing, and late chick rearing) was characterized by distinct trends or levels of behavior. During egg laying, female attentiveness to tile nest increased, and male attentiveness decreased. Throughout incubation and the first several days of early chick rearing, females were highly attentive to their nests, whereas males rarely entered the nest cavities. Female attentiveness then began to decline. Male attentiveness to the nest was sporadic until chicks were 10-12 days old. when all males began to enter their nests at least once each day. During late chick rearing, both male and female attentiveness were erratic and highly variable. Biologists may be able to use these results to identify nest problems and the need for management intervention when patterns of nest attentiveness deviate from the limits described in this study..

  20. Can selection on nest size from nest predation explain the latitudinal gradient in clutch size?

    Science.gov (United States)

    Biancucci, L.; Martin, T.E.

    2010-01-01

    1. Latitudinal variation in clutch sizes of birds is a well described, but poorly understood pattern. Many hypotheses have been proposed, but few have been experimentally tested, and none have been universally accepted by researchers. 2. The nest size hypothesis posits that higher nest predation in the tropics favours selection for smaller nests and thereby constrains clutch size by shrinking available space for eggs and/or nestlings in the nest. We tested this hypothesis with an experiment in a tropical forest and a comparative study between temperate and tropical field sites. 3. Specifically, we tested if: (i) predation increased with nest size; (ii) tropical birds had smaller nests controlled for body size; and (iii) clutch size was explained by nest size controlled for body size. 4. Experimental swapping of nests of different sizes showed that nest predation increased with nest size in the tropical site. Moreover, nest predation rates were higher in species with larger nests in both sites. However, nest size, corrected for body mass and phylogeny, did not differ between sites and was not related to clutch size between sites. 5. Hence, nest predation can exert selection on nest size as predicted by the hypothesis. Nest size increased with adult body mass, such that adult size might indirectly influence reproductive success through effects on nest size and nest predation risk. Ultimately, however, selection from nest predation on nest size does not explain the smaller clutch sizes typical of the tropics.

  1. Nested Dynamic Condition Response Graphs

    DEFF Research Database (Denmark)

    Hildebrandt, Thomas; Mukkamala, Raghava Rao; Slaats, Tijs

    2012-01-01

    We present an extension of the recently introduced declarative process model Dynamic Condition Response Graphs ( DCR Graphs) to allow nested subgraphs and a new milestone relation between events. The extension was developed during a case study carried out jointly with our industrial partner...... Exformatics, a danish provider of case and workflow management systems. We formalize the semantics by giving first a map from Nested to (flat) DCR Graphs with milestones, and then extending the previously given mapping from DCR Graphs to Buchi-automata to include the milestone relation....

  2. Automated Forensic Animal Family Identification by Nested PCR and Melt Curve Analysis on an Off-the-Shelf Thermocycler Augmented with a Centrifugal Microfluidic Disk Segment.

    Science.gov (United States)

    Keller, Mark; Naue, Jana; Zengerle, Roland; von Stetten, Felix; Schmidt, Ulrike

    2015-01-01

    Nested PCR remains a labor-intensive and error-prone biomolecular analysis. Laboratory workflow automation by precise control of minute liquid volumes in centrifugal microfluidic Lab-on-a-Chip systems holds great potential for such applications. However, the majority of these systems require costly custom-made processing devices. Our idea is to augment a standard laboratory device, here a centrifugal real-time PCR thermocycler, with inbuilt liquid handling capabilities for automation. We have developed a microfluidic disk segment enabling an automated nested real-time PCR assay for identification of common European animal groups adapted to forensic standards. For the first time we utilize a novel combination of fluidic elements, including pre-storage of reagents, to automate the assay at constant rotational frequency of an off-the-shelf thermocycler. It provides a universal duplex pre-amplification of short fragments of the mitochondrial 12S rRNA and cytochrome b genes, animal-group-specific main-amplifications, and melting curve analysis for differentiation. The system was characterized with respect to assay sensitivity, specificity, risk of cross-contamination, and detection of minor components in mixtures. 92.2% of the performed tests were recognized as fluidically failure-free sample handling and used for evaluation. Altogether, augmentation of the standard real-time thermocycler with a self-contained centrifugal microfluidic disk segment resulted in an accelerated and automated analysis reducing hands-on time, and circumventing the risk of contamination associated with regular nested PCR protocols.

  3. Patterns of magpie nest utilization by a nesting raptor community in a secondary forest

    Institute of Scientific and Technical Information of China (English)

    Tong Zhou; Haitao Wang; Yu Liu; Fumin Lei; Wei Gao

    2009-01-01

    For a total of 9 years, we examined the patterns of a nesting raptor community that utilized European Magpie (Pica pica) nests in the Zuojia Natural Reserve, northeast China. Eight raptor species and two other bird species were recorded nesting in magpie nests. The reuse rate of abandoned magpie nests was 51.6%, and the number of reused nests was positively correlated with their availability. Raptors utilized 83.3% of the reused abandoned magpie nests. Nests followed for more than 1 year were reused by raptors an average of 1.13 times. Inter-specific nest usurpation was common, with 17.3% of new magpie nests being usurped by raptors, and four cases of usurpation occurred among different raptor species. At the community level, 8 of 11 raptor species took over magpie nests to breed in the study area, and 91.9% of their nests came from magpie nests. European Magpies represent the core species in the nest web of the local raptor community that utilizes magpie nests. At the forest stand level, closer proximity to forest edges and greater distances from occupied raptor nests were the best predictors of nest reuse. At the nest-site level, arbor density and canopy coverage were the best predictors of nest reuse.

  4. Unusual raptor nests around the world

    Science.gov (United States)

    Ellis, D.H.; Craig, T.; Craig, E.; Postupalsky, S.; LaRue, C.T.; Nelson, R.W.; Anderson, D.W.; Henny, C.J.; Watson, J.; Millsap, B.A.; Dawson, J.W.; Cole, K.L.; Martin, E.M.; Margalida, A.; Kung, P.

    2009-01-01

    From surveys in many countries, we report raptors using unusual nesting materials (e.g., paper money, rags, metal, antlers, and large bones) and unusual nesting situations. For example, we documented nests of Steppe Eagles Aquila nipalensis and Upland Buzzards Buteo hemilasius on the ground beside well-traveled roads, Saker Falcon Falco cherrug eyries in attics and a cistern, and Osprey Pandion haliaetus nests on the masts of boats and on a suspended automobile. Other records include a Golden Eagle A. chrysaetos nest 7.0 m in height, believed to be the tallest nest ever described, and, for the same species, we report nesting in rudimentary nests. Some nest sites are within a few meters of known predators or competitors. These unusual observations may be important in revealing the plasticity of a species' behavioral repertoire. ?? 2009 The Raptor Research Foundation, Inc.

  5. Instantiation Schemes for Nested Theories

    CERN Document Server

    Echenim, Mnacho

    2011-01-01

    This paper investigates under which conditions instantiation-based proof procedures can be combined in a nested way, in order to mechanically construct new instantiation procedures for richer theories. Interesting applications in the field of verification are emphasized, particularly for handling extensions of the theory of arrays.

  6. Development with age of nest box use and gregarious nesting in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2010-01-01

    Use of nest boxes is an important part of the behavioural repertoire of laying hens kept under commercial conditions. A special form of nest box use is gregarious nesting, which occurs when a hen given the choice between an occupied and an unoccupied nest site chooses the occupied nest site...... experiences in selection of nest locations, causing the found decrease in frequency of gregarious nesting after age 20 weeks. A general preference for corner and end nest boxes is suggested to have triggered the initial use of the left nest box by the first hens coming into lay and to have maintained...... risk of broken or dirty eggs. The main objectives were to investigate the use of nest boxes according to their position and the occurrence of gregarious nesting with age. Twelve groups of 15 Isa Warren hens were housed in pens each containing three adjacent roll-out nest boxes only differing...

  7. Influence of Habitat Types on Prairie Nesting Waterfowl Nest Density and Nest Success in Northeastern North Dakota, 2010 – 2013

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Nest density and nest success of ducks in native and non-native grasslands within the Devils Lake WMD, Northeastern North Dakota. Waterfowl representing 8 species of...

  8. Micro-Fluidic Dye Ring Laser - Experimental Tuning of the Wavelength and Numerical Simulation of the Cavity Modes

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger

    2006-01-01

    We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view.......We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view....

  9. Importance Nested Sampling and the MultiNest Algorithm

    CERN Document Server

    Feroz, F; Cameron, E; Pettitt, A N

    2013-01-01

    Bayesian inference involves two main computational challenges. First, in estimating the parameters of some model for the data, the posterior distribution may well be highly multi-modal: a regime in which the convergence to stationarity of traditional Markov Chain Monte Carlo (MCMC) techniques becomes incredibly slow. Second, in selecting between a set of competing models the necessary estimation of the Bayesian evidence for each is, by definition, a (possibly high-dimensional) integration over the entire parameter space; again this can be a daunting computational task, although new Monte Carlo (MC) integration algorithms offer solutions of ever increasing efficiency. Nested sampling (NS) is one such contemporary MC strategy targeted at calculation of the Bayesian evidence, but which also enables posterior inference as a by-product, thereby allowing simultaneous parameter estimation and model selection. The widely-used MultiNest algorithm presents a particularly efficient implementation of the NS technique for...

  10. First experimental demonstration of a Self-Oscillating Fluidic Heat Engine (SOFHE) with piezoelectric power generation

    Science.gov (United States)

    Monin, T.; Tessier-Poirier, A.; Léveillé, E.; Juneau-Fecteau, A.; Skotnicki, T.; Formosa, F.; Monfray, S.; Fréchette, L. G.

    2016-11-01

    In this paper, we present the working principle and first experimental demonstration of an innovative approach to harvest low-quality heat sources, the Self-Oscillating Fluidic Heat Engine (SOFHE). Thermal energy is first converted into pressure pulsations by a selfexcited thermo-fluidic oscillator driven by periodic phase change of a fluid in an enclosed channel. A piezoelectric membrane then converts this mechanical energy into an electrical power. After describing the working principle, an experimental demonstration is presented. The P-V diagram of this new thermodynamic cycle is measured, showing a mechanical power of 3.3mW. Combined with a piezoelectric spiral membrane, the converted electrical power generation achieved is close to 1μ W in a 1MΩ load. This work sets the basis for future development of this new type of heat engine for waste heat recovery and to power wireless sensors.

  11. A One-Dimensional Fluidic Nanogenerator with a High Power Conversion Efficiency.

    Science.gov (United States)

    Xu, Yifan; Chen, Peining; Zhang, Jing; Xie, Songlin; Wan, Fang; Deng, Jue; Cheng, Xunliang; Hu, Yajie; Liao, Meng; Wang, Bingjie; Sun, Xuemei; Peng, Huisheng

    2017-08-26

    Electricity generation from flowing water has been developed for over a century and plays a critical role in our lives. Generally, heavy and complex facilities are required for electricity generation, while using these technologies for applications that require a small size and high flexibility is difficult. Here, we developed a fluidic nanogenerator fiber from an aligned carbon nanotube sheet to generate electricity from any flowing water source in the environment as well as in the human body. The power conversion efficiency reached 23.3 %. The fluidic nanogenerator fiber was flexible and stretchable, and the high performance was well-maintained after deformation over 1 000 000 cycles. The fiber also offered unique and promising advantages, such as the ability to be woven into fabrics for large-scale applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fluidic and air-stable supported lipid bilayer and cell-mimicking microarrays.

    Science.gov (United States)

    Deng, Yang; Wang, Yini; Holtz, Bryan; Li, Jingyi; Traaseth, Nathan; Veglia, Gianluigi; Stottrup, Benjamin J; Elde, Robert; Pei, Duanqing; Guo, Athena; Zhu, X-Y

    2008-05-14

    As drug delivery, therapy, and medical imaging are becoming increasingly cell-specific, there is a critical need for high fidelity and high-throughput screening methods for cell surface interactions. Cell membrane-mimicking surfaces, i.e., supported lipid bilayers (SLBs), are currently not sufficiently robust to meet this need. Here we describe a method of forming fluidic and air-stable SLBs through tethered and dispersed cholesterol groups incorporated into the bottom leaflet. Achieving air stability allows us to easily fabricate SLB microarrays from direct robotic spotting of vesicle solutions. We demonstrate their application as cell membrane-mimicking microarrays by reconstituting peripheral as well as integral membrane components that can be recognized by their respective targets. These demonstrations establish the viability of the fluidic and air-stable SLB platform for generating content microarrays in high throughput studies, e.g., the screening of drugs and nanomedicine targeting cell surface receptors.

  13. Adaptive optics correction of a tunable fluidic lens for ophthalmic applications

    Science.gov (United States)

    Fuh, Yiin-Kuen; Lin, Ming-Xin

    2013-11-01

    Tunable fluidic lenses are utilizing curvature change via continuously adjusting injected liquid volumes to achieve variable-focusing properties. Nevertheless, the nature of curvature change and refractive index mismatch causes inherent spatial aberrations that severely degrade image quality. Here we present the experimental study of the aberrations in tunable fluidic lenses and use of adaptive optics to compensate for the wavefront errors. Adaptive optics based scheme is demonstrated for three injected liquid volumes, resulting in a substantial reduction of the wavefront errors from 0.42, 1.05, 1.49 to 0.20, 0.21, 0.23 μm, respectively, corresponding to the focal length tunability of 100-200 mm.

  14. Numerical Simulation of a High-Lift Configuration with Embedded Fluidic Actuators

    Science.gov (United States)

    Vatsa, Veer N.; Casalino, Damiano; Lin, John C.; Appelbaum, Jason

    2014-01-01

    Numerical simulations have been performed for a vertical tail configuration with deflected rudder. The suction surface of the main element of this configuration is embedded with an array of 32 fluidic actuators that produce oscillating sweeping jets. Such oscillating jets have been found to be very effective for flow control applications in the past. In the current paper, a high-fidelity computational fluid dynamics (CFD) code known as the PowerFLOW(Registered TradeMark) code is used to simulate the entire flow field associated with this configuration, including the flow inside the actuators. The computed results for the surface pressure and integrated forces compare favorably with measured data. In addition, numerical solutions predict the correct trends in forces with active flow control compared to the no control case. Effect of varying yaw and rudder deflection angles are also presented. In addition, computations have been performed at a higher Reynolds number to assess the performance of fluidic actuators at flight conditions.

  15. Evaluation of the threshold trimming method for micro inertial fluidic switch based on electrowetting technology

    Directory of Open Access Journals (Sweden)

    Tingting Liu

    2014-03-01

    Full Text Available The switch based on electrowetting technology has the advantages of no moving part, low contact resistance, long life and adjustable acceleration threshold. The acceleration threshold of switch can be fine-tuned by adjusting the applied voltage. This paper is focused on the electrowetting properties of switch and the influence of microchannel structural parameters, applied voltage and droplet volume on acceleration threshold. In the presence of process errors of micro inertial fluidic switch and measuring errors of droplet volume, there is a deviation between test acceleration threshold and target acceleration threshold. Considering the process errors and measuring errors, worst-case analysis is used to analyze the influence of parameter tolerance on the acceleration threshold. Under worst-case condition the total acceleration threshold tolerance caused by various errors is 9.95%. The target acceleration threshold can be achieved by fine-tuning the applied voltage. The acceleration threshold trimming method of micro inertial fluidic switch is verified.

  16. Ultrafast synthesis of LTA nanozeolite using a two-phase segmented fluidic microreactor.

    Science.gov (United States)

    Zhou, Jianhai; Jiang, Hao; Xu, Jian; Hu, Jun; Liu, Honglai; Hu, Ying

    2013-08-01

    Fast synthesis of nanosized zeolite is desirable for many industrial applications. An ultrafast synthesis of LTA nanozeolite by the organic-additive-free method in a two-phase segmented fluidic microreactor has been realized. The results reveal that the obtained LTA nanozeolites through microreactor are much smaller and higher crystallinity than those under similar conditions through conventional macroscale batch reactor. By investing various test conditions, such as the crystallization temperature, the flow rate, the microchannel length, and the aging time of gel solution, this two-phase segmented fluidic microreactor system enables us to develop an ultrafast method for nanozeolite production. Particularly, when using a microreactor with the microchannel length of 20 m, it only takes 10 min for the crystallization and no aging process to successfully produce the crystalline LTA nanozeolites at 95 degrees C.

  17. Micro fluidic System for Culturing and Monitoring of Neuronal Cells and Tissue

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Waagepetersen, Helle S.

    . Tests show that the function of neurons cultured on PNWs lies closer to neurons in vivo than neurons cultured on conventional plastic substrates. The second part of the thesis describes a fluidic system for culturing of brain slices. It describes the fabrication and use of the system as well as results...... for culturing of brain tissue. The second goal was to develop a sensor system with the potential for incorporation into both conventional culture systems and fluidic culturing systems. The third and final goal of this project was to develop a system for culturing of neuronal cells with the possibility...... neuronal cells on a Peptide Nano Wires (PNW) modified substrate aiming to bring conventional neuronal cultures closer to mimic the in vivo situation. The work describes both the fabrication of the culture substrates and results comparing the performance of PNWcultured neurons and conventional cultures...

  18. Induced fluid rotation and bistable fluidic turn-down valves (a survey

    Directory of Open Access Journals (Sweden)

    Tesař Václav

    2015-01-01

    Full Text Available Paper surveys engineering applications of an unusual fluidic principle — momentum transfer through a relatively small communicating window into a vortex chamber, where the initially stationary fluid is put into rotation. The transfer is often by shear stress acting in the window plane, but may be enhanced and perhaps even dominated by fluid flow crossing the boundary. The case of zero-time-mean fluid transport through the window has found use in experimental fluid mechanics: non-invasive measurement of wall shear stress on objects by evaluating the induced rotation in the vortex chamber. The case with the non-zero flow through the interface became the starting point in development of fluidic valves combining two otherwise mutually incompatible properties: bistability and flow turning down.

  19. Ouray National Wildlife Refuge : Duck nesting survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary report of the 1991 duck nest survey at Ouray National Wildlife Refuge. Key areas of the refuge were nest searched during the period between May 25th and July...

  20. The laboratory stand for didactic and research of a Fluidic Muscle

    Directory of Open Access Journals (Sweden)

    P. Zub

    2007-12-01

    Full Text Available Purpose: The aim of this work was to design and build a laboratory stand dedicated for didactic and research purposes connected with a Fluidic Muscle. The stand is placed at the Electropneumatic and PLC controllers Laboratory [10,11,12] of the Institute of Engineering Processes Automation and Integrated Manufacturing Systems of the Faculty of Mechanical Engineering of the Silesian University of Technology, Gliwice, Poland.Design/methodology/approach: The stand was designed and visualised by utilisation of professional CAD software – CATIA and a fluidic muscle was chosen according to a MuscleSIM programme of FESTO company.Findings: The device integrates the elements which are indispensable determinant of contemporary industry and the main aim of its construction was to bring closer conceptions and ideas connected with the construction and the outworking of the fluidic muscle, problems of proportional pressure control, visualisation and control of the industrial processes as well as making possible of carrying out the investigations and experiments on these elements.Research limitations/implications: The module structure of the research stand gives possibility to make its further development by adding extra modules that can be easily mounted on plates, which will make possible the implementation of series of individual positions controlled by one PLC. Thanks to the applied system of visualisation, switching among synoptic screens is possible. The visualisation represents every separate module of the stand and so, with the help of one operator position, gives possibility to control every chosen module of the whole device.Originality/value: The mechatronic didactic and research device introduced in the paper represents the new approach to the problem of visualisation and control of the fluidic muscle and constitutes the perfect tool of the aided didactic process in the Institute’s laboratory

  1. Manufacturing Techniques for Producing High Quality Fluidic Laminates at Low Cost.

    Science.gov (United States)

    1980-09-02

    1473 EDITION OF INOV GS OOETE UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE IP.I1 *I@ %.#* " t UNCLASSIFIED SECURITY CLASIIrCATION OF THIS PAGI[(Wm...metal not protected by the photo-resist material to create the fluidic laminate. 1 Photochemical etching is the process used extensively in the...electronic industry for printed circuit board manufacture. This process involves coating the sur- face of the material to be etched with a photo-sensitive

  2. Sorting it out: bedding particle size and nesting material processing method affect nest complexity.

    Science.gov (United States)

    Robinson-Junker, Amy; Morin, Amelia; Pritchett-Corning, Kathleen; Gaskill, Brianna N

    2017-04-01

    As part of routine husbandry, an increasing number of laboratory mice receive nesting material in addition to standard bedding material in their cages. Nesting material improves health outcomes and physiological performance in mice that receive it. Providing usable nesting material uniformly and efficiently to various strains of mice remains a challenge. The aim of this study was to determine how bedding particle size, method of nesting material delivery, and processing of the nesting material before delivery affected nest building in mice of strong (BALB/cAnNCrl) and weak (C3H/HeNCrl) gathering abilities. Our data suggest that processing nesting material through a grinder in conjunction with bedding material, although convenient for provision of bedding with nesting material 'built-in', negatively affects the integrity of the nesting material and subsequent nest-building outcomes. We also found that C3H mice, previously thought to be poor nest builders, built similarly scored nests to those of BALB/c mice when provided with unprocessed nesting material. This was true even when nesting material was mixed into the bedding substrate. We also observed that when nesting material was mixed into the bedding substrate, mice of both strains would sort their bedding by particle size more often than if it were not mixed in. Our findings support the utility of the practice of distributing nesting material mixed in with bedding substrate, but not that of processing the nesting material with the bedding in order to mix them.

  3. Nested Quantum Error Correction Codes

    CERN Document Server

    Wang, Zhuo; Fan, Hen; Vedral, Vlatko

    2009-01-01

    The theory of quantum error correction was established more than a decade ago as the primary tool for fighting decoherence in quantum information processing. Although great progress has already been made in this field, limited methods are available in constructing new quantum error correction codes from old codes. Here we exhibit a simple and general method to construct new quantum error correction codes by nesting certain quantum codes together. The problem of finding long quantum error correction codes is reduced to that of searching several short length quantum codes with certain properties. Our method works for all length and all distance codes, and is quite efficient to construct optimal or near optimal codes. Two main known methods in constructing new codes from old codes in quantum error-correction theory, the concatenating and pasting, can be understood in the framework of nested quantum error correction codes.

  4. 3D printed fluidics with embedded analytic functionality for automated reaction optimisation

    Science.gov (United States)

    Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D

    2017-01-01

    Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis. PMID:28228852

  5. 3D printed fluidics with embedded analytic functionality for automated reaction optimisation.

    Science.gov (United States)

    Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D; Christie, Steven D R

    2017-01-01

    Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

  6. 3D printed fluidics with embedded analytic functionality for automated reaction optimisation

    Directory of Open Access Journals (Sweden)

    Andrew J. Capel

    2017-01-01

    Full Text Available Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

  7. Improving acoustic streaming effects in fluidic systems by matching SU-8 and polydimethylsiloxane layers.

    Science.gov (United States)

    Catarino, S O; Minas, G; Miranda, J M

    2016-07-01

    This paper reports the use of acoustic waves for promoting and improving streaming in tridimensional polymethylmethacrylate (PMMA) cuvettes of 15mm width×14mm height×2.5mm thickness. The acoustic waves are generated by a 28μm thick poly(vinylidene fluoride) - PVDF - piezoelectric transducer in its β phase, actuated at its resonance frequency: 40MHz. The acoustic transmission properties of two materials - SU-8 and polydimethylsiloxane (PDMS) - were numerically compared. It was concluded that PDMS inhibits, while SU-8 allows, the transmission of the acoustic waves to the propagation medium. Therefore, by simulating the acoustic transmission properties of different materials, it is possible to preview the acoustic behavior in the fluidic system, which allows the optimization of the best layout design, saving costs and time. This work also presents a comparison between numerical and experimental results of acoustic streaming obtained with that β-PVDF transducer in the movement and in the formation of fluid recirculation in tridimensional closed domains. Differences between the numerical and experimental results are credited to the high sensitivity of acoustic streaming to the experimental conditions and to limitations of the numerical method. The reported study contributes for the improvement of simulation models that can be extremely useful for predicting the acoustic effects of new materials in fluidic devices, as well as for optimizing the transducers and matching layers positioning in a fluidic structure.

  8. An Undecidable Nested Recurrence Relation

    CERN Document Server

    Celaya, Marcel

    2012-01-01

    Roughly speaking, a recurrence relation is nested if it contains a subexpression of the form ... A(...A(...)...). Many nested recurrence relations occur in the literature, and determining their behavior seems to be quite difficult and highly dependent on their initial conditions. A nested recurrence relation A(n) is said to be undecidable if the following problem is undecidable: given a finite set of initial conditions for A(n), is the recurrence relation calculable? Here calculable means that for every n >= 0, either A(n) is an initial condition or the calculation of A(n) involves only invocations of A on arguments in {0,1,...,n-1}. We show that the recurrence relation A(n) = A(n-4-A(A(n-4)))+4A(A(n-4)) +A(2A(n-4-A(n-2))+A(n-2)). is undecidable by showing how it can be used, together with carefully chosen initial conditions, to simulate Post 2-tag systems, a known Turing complete problem.

  9. Supramolecular nesting of cyclic polymers.

    Science.gov (United States)

    Kondratuk, Dmitry V; Perdigão, Luís M A; Esmail, Ayad M S; O'Shea, James N; Beton, Peter H; Anderson, Harry L

    2015-04-01

    Advances in template-directed synthesis make it possible to create artificial molecules with protein-like dimensions, directly from simple components. These synthetic macromolecules have a proclivity for self-organization that is reminiscent of biopolymers. Here, we report the synthesis of monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C–C bonds). The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organization, combining encapsulation and nesting; one nanoring adopts a near-circular conformation, thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions there is stacking or nesting, but not a combination of both.

  10. Nesting behavior of the poo-uli

    Science.gov (United States)

    Kepler, C.B.; Pratt, T.K.; Ecton, A.M.; Engilis, A.; Fluetsch, K.M.

    1996-01-01

    We describe two sequential nestings of a pair of Poo-uli (Melamprosops phaeosoma), a Hawaiian honeycreeper nearing extinction. Similarities to nesting of most other honeycreepers included: nest site in ohia lehua (Metrosideros polymorpha Gaud.) canopy; breeding in March through June; monogamous breeding system with the putative male helping build the nest, feeding the putative female throughout each nesting event, and feeding the chicks, but not incubating or brooding; and complete nest sanitation. Notable differences were the paucity of songs and calls by the parents and inclusion of snails in the diet of nestlings. Clutch size was probably two eggs for both nests. High winds, rain, or both influenced parental behavior: the female stayed longer on the nest and took shorter recesses in poor weather. Weather did not affect rates at which the male fed the female on the nest; however, the feeding rate increased from the egg to the chick stage probably because food was passed on to the chicks. At nest #2, parents fed young chicks (<14 days old) more often in good than in poor weather; data were insufficient for old chicks. Weather is usually poor throughout the year in the relictual range of the Poo-uli and is likely to impact nesting success. The first nest failed in poor weather. The second fledged a single young 21 days old. Diet of nestlings appeared to consist of a higher proportion of insect larvae than that of older birds, which are reported to eat mostly snails.

  11. On the Denesting of Nested Square Roots

    Science.gov (United States)

    Gkioulekas, Eleftherios

    2017-01-01

    We present the basic theory of denesting nested square roots, from an elementary point of view, suitable for lower level coursework. Necessary and sufficient conditions are given for direct denesting, where the nested expression is rewritten as a sum of square roots of rational numbers, and for indirect denesting, where the nested expression is…

  12. Nest Material Shapes Eggs Bacterial Environment.

    Directory of Open Access Journals (Sweden)

    Cristina Ruiz-Castellano

    Full Text Available Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus of eggshells in nests of spotless starlings (Sturnus unicolor at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and

  13. Effect of heterogeneity of nest boxes on occurrence of gregarious nesting in laying hens

    DEFF Research Database (Denmark)

    Clausen, Tina; Riber, Anja Brinch

    2012-01-01

    Gregarious nesting, where hens select already occupied nest boxes even when other nest boxes are unoccupied, is an unwanted behaviour in laying hens that may reduce animal welfare and pose a financial cost to the producer. It has been suggested that gregarious nesting is caused by the difficulties...... experienced by hens in distinguishing between nest boxes in long rows of identical boxes. Heterogeneity of nest boxes has therefore been suggested as a method to reduce gregarious nesting. To test this hypothesis two experiments were performed. Twelve groups of 13–15 ISA Warren hens 27 weeks of age were...... nesting was higher in experimental groups compared to control groups (P laying period did not differ between the experimental and control groups (P = 0.41). Numbers of visits to and eggs laid in nest boxes positioned either left or right were higher compared to nest boxes positioned...

  14. Performance Analysis of a Fluidic Axial Oscillation Tool for Friction Reduction with the Absence of a Throttling Plate

    Directory of Open Access Journals (Sweden)

    Xinxin Zhang

    2017-04-01

    Full Text Available An axial oscillation tool is proved to be effective in solving problems associated with high friction and torque in the sliding drilling of a complex well. The fluidic axial oscillation tool, based on an output-fed bistable fluidic oscillator, is a type of axial oscillation tool which has become increasingly popular in recent years. The aim of this paper is to analyze the dynamic flow behavior of a fluidic axial oscillation tool with the absence of a throttling plate in order to evaluate its overall performance. In particular, the differences between the original design with a throttling plate and the current default design are profoundly analyzed, and an improvement is expected to be recorded for the latter. A commercial computational fluid dynamics code, Fluent, was used to predict the pressure drop and oscillation frequency of a fluidic axial oscillation tool. The results of the numerical simulations agree well with corresponding experimental results. A sufficient pressure pulse amplitude with a low pressure drop is desired in this study. Therefore, a relative pulse amplitude of pressure drop and displacement are introduced in our study. A comparison analysis between the two designs with and without a throttling plate indicates that when the supply flow rate is relatively low or higher than a certain value, the fluidic axial oscillation tool with a throttling plate exhibits a better performance; otherwise, the fluidic axial oscillation tool without a throttling plate seems to be a preferred alternative. In most of the operating circumstances in terms of the supply flow rate and pressure drop, the fluidic axial oscillation tool performs better than the original design.

  15. Nest predation increases with parental activity: separating nest site and parental activity effects.

    OpenAIRE

    Martin, T E; Scott, J; Menge, C

    2000-01-01

    Alexander Skutch hypothesized that increased parental activity can increase the risk of nest predation. We tested this hypothesis using ten open-nesting bird species in Arizona, USA. Parental activity was greater during the nestling than incubation stage because parents visited the nest frequently to feed their young during the nestling stage. However, nest predation did not generally increase with parental activity between nesting stages across the ten study species. Previous investigators h...

  16. Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

    Science.gov (United States)

    Hollander, Franck A; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

    2015-01-01

    In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

  17. DNest3: Diffusive Nested Sampling

    Science.gov (United States)

    Brewer, Brendon

    2016-04-01

    DNest3 is a C++ implementation of Diffusive Nested Sampling (ascl:1010.029), a Markov Chain Monte Carlo (MCMC) algorithm for Bayesian Inference and Statistical Mechanics. Relative to older DNest versions, DNest3 has improved performance (in terms of the sampling overhead, likelihood evaluations still dominate in general) and is cleaner code: implementing new models should be easier than it was before. In addition, DNest3 is multi-threaded, so one can run multiple MCMC walkers at the same time, and the results will be combined together.

  18. Nested-cone transformer antenna

    Science.gov (United States)

    Ekdahl, Carl A.

    1991-01-01

    A plurality of conical transmission lines are concentrically nested to form n output antenna for pulsed-power, radio-frequency, and microwave sources. The diverging conical conductors enable a high power input density across a bulk dielectric to be reduced below a breakdown power density at the antenna interface with the transmitting medium. The plurality of cones maintain a spacing between conductors which minimizes the generation of high order modes between the conductors. Further, the power input feeds are isolated at the input while enabling the output electromagnetic waves to add at the transmission interface. Thus, very large power signals from a pulse rf, or microwave source can be radiated.

  19. Open and closed-loop control of transonic buffet on 3D turbulent wings using fluidic devices

    Science.gov (United States)

    Dandois, Julien; Lepage, Arnaud; Dor, Jean-Bernard; Molton, Pascal; Ternoy, Frédéric; Geeraert, Arnaud; Brunet, Vincent; Coustols, Éric

    2014-06-01

    This paper presents an overview of the work performed recently at ONERA on the control of the buffet phenomenon. This aerodynamic instability induces strong wall pressure fluctuations and as such limits aircraft envelope; consequently, it is interesting to try to delay its onset, in order to enlarge aircraft flight envelop, but also to provide more flexibility during the design phase. Several types of flow control have been investigated, either passive (mechanical vortex generators) or active (fluidic VGs, fluidic trailing-edge device (TED)). It is shown than mechanical and fluidic VGs are able to delay buffet onset in the angle-of-attack domain by suppressing the separation downstream of the shock. The effect of the fluidic TED is different, the separation is not suppressed, but the rear wing loading is increased and consequently the buffet onset is not delayed to higher angles of attack, but only to higher lift coefficient. Then, a closed loop control methodology based on a quasi-static approach is defined and several architectures are tested for various parameters such as the input signal, the objective function or, the tuning of the feedback gain. All closed loop methods are implemented on a dSPACE device calculating in real time the fluidic actuators command from the unsteady pressure sensors data.

  20. Polytypic Functions Over Nested Datatypes

    Directory of Open Access Journals (Sweden)

    Ralf Hinze

    1999-12-01

    Full Text Available The theory and practice of polytypic programming is intimately connected with the initial algebra semantics of datatypes. This is both a blessing and a curse. It is a blessing because the underlying theory is beautiful and well developed. It is a curse because the initial algebra semantics is restricted to so-called regular datatypes. Recent work by R. Bird and L. Meertens [3] on the semantics of non-regular or nested datatypes suggests that an extension to general datatypes is not entirely straightforward. Here we propose an alternative that extends polytypism to arbitrary datatypes, including nested datatypes and mutually recursive datatypes. The central idea is to use rational trees over a suitable set of functor symbols as type arguments for polytypic functions. Besides covering a wider range of types the approach is also simpler and technically less involving than previous ones. We present several examples of polytypic functions, among others polytypic reduction and polytypic equality. The presentation assumes some background in functional and in polytypic programming. A basic knowledge of monads is required for some of the examples.

  1. Eggs in the Freezer: Energetic Consequences of Nest Site and Nest Design in Arctic Breeding Shorebirds

    Science.gov (United States)

    Tulp, Ingrid; Schekkerman, Hans; de Leeuw, Joep

    2012-01-01

    Birds construct nests for several reasons. For species that breed in the Arctic, the insulative properties of nests are very important. Incubation is costly there and due to an increasing surface to volume ratio, more so in smaller species. Small species are therefore more likely to place their nests in thermally favourable microhabitats and/or to invest more in nest insulation than large species. To test this hypothesis, we examined characteristics of nests of six Arctic breeding shorebird species. All species chose thermally favourable nesting sites in a higher proportion than expected on the basis of habitat availability. Site choice did not differ between species. Depth to frozen ground, measured near the nests, decreased in the course of the season at similar non-species-specific speeds, but this depth increased with species size. Nest cup depth and nest scrape depth (nest cup without the lining) were unrelated to body mass (we applied an exponent of 0.73, to account for metabolic activity of the differently sized species). Cup depth divided by diameter2 was used as a measure of nest cup shape. Small species had narrow and deep nests, while large species had wide shallow nests. The thickness of nest lining varied between 0.1 cm and 7.6 cm, and decreased significantly with body mass. We reconstruct the combined effect of different nest properties on the egg cooling coefficient using previously published quantitative relationships. The predicted effect of nest cup depth and lining depth on heat loss to the frozen ground did not correlate with body mass, but the sheltering effect of nest cup diameter against wind and the effects of lining material on the cooling coefficient increased with body mass. Our results suggest that small arctic shorebirds invest more in the insulation of their nests than large species. PMID:22701596

  2. Design Enhancements of the Two-Dimensional, Dual Throat Fluidic Thrust Vectoring Nozzle Concept

    Science.gov (United States)

    Flamm, Jeffrey D.; Deere, Karen A.; Mason, Mary L.; Berrier, Bobby L.; Johnson, Stuart K.

    2006-01-01

    A Dual Throat Nozzle fluidic thrust vectoring technique that achieves higher thrust-vectoring efficiencies than other fluidic techniques, without sacrificing thrust efficiency has been developed at NASA Langley Research Center. The nozzle concept was designed with the aid of the structured-grid, Reynolds-averaged Navier-Stokes computational fluidic dynamics code PAB3D. This new concept combines the thrust efficiency of sonic-plane skewing with increased thrust-vectoring efficiencies obtained by maximizing pressure differentials in a separated cavity located downstream of the nozzle throat. By injecting secondary flow asymmetrically at the upstream minimum area, a new aerodynamic minimum area is formed downstream of the geometric minimum and the sonic line is skewed, thus vectoring the exhaust flow. The nozzle was tested in the NASA Langley Research Center Jet Exit Test Facility. Internal nozzle performance characteristics were defined for nozzle pressure ratios up to 10, with a range of secondary injection flow rates up to 10 percent of the primary flow rate. Most of the data included in this paper shows the effect of secondary injection rate at a nozzle pressure ratio of 4. The effects of modifying cavity divergence angle, convergence angle and cavity shape on internal nozzle performance were investigated, as were effects of injection geometry, hole or slot. In agreement with computationally predicted data, experimental data verified that decreasing cavity divergence angle had a negative impact and increasing cavity convergence angle had a positive impact on thrust vector angle and thrust efficiency. A curved cavity apex provided improved thrust ratios at some injection rates. However, overall nozzle performance suffered with no secondary injection. Injection holes were more efficient than the injection slot over the range of injection rates, but the slot generated larger thrust vector angles for injection rates less than 4 percent of the primary flow rate.

  3. Electrochemiluminescence at Bare and DNA-Coated Graphite Electrodes in 3D-Printed Fluidic Devices.

    Science.gov (United States)

    Bishop, Gregory W; Satterwhite-Warden, Jennifer E; Bist, Itti; Chen, Eric; Rusling, James F

    Clear plastic fluidic devices with ports for incorporating electrodes to enable electrochemiluminescence (ECL) measurements were prepared using a low-cost, desktop three-dimensional (3D) printer based on stereolithography. Electrodes consisted of 0.5 mm pencil graphite rods and 0.5 mm silver wires inserted into commercially available 1/4 in.-28 threaded fittings. A bioimaging system equipped with a CCD camera was used to measure ECL generated at electrodes and small arrays using 0.2 M phosphate buffer solutions containing tris(2,2'-bipyridyl)dichlororuthenium(II) hexahydrate ([Ru(bpy)3](2+)) with 100 mM tri-n-propylamine (TPA) as the coreactant. ECL signals produced at pencil graphite working electrodes were linear with respect to [Ru(bpy)3](2+) concentration for 9-900 μM [Ru(bpy)3](2+). The detection limit was found to be 7 μM using the CCD camera with exposure time set at 10 s. Electrode-to-electrode ECL signals varied by ±7.5%. Device performance was further evaluated using pencil graphite electrodes coated with multilayer poly(diallyldimethylammonium chloride) (PDDA)/DNA films. In these experiments, ECL resulted from the reaction of [Ru(bpy)3](3+) with guanines of DNA. ECL produced at these thin-film electrodes was linear with respect to [Ru(bpy)3](2+) concentration from 180 to 800 μM. These studies provide the first demonstration of ECL measurements obtained using a 3D-printed closed-channel fluidic device platform. The affordable, high-resolution 3D printer used in these studies enables easy, fast, and adaptable prototyping of fluidic devices capable of incorporating electrodes for measuring ECL.

  4. Nested Canalizing Functions and Their Networks

    CERN Document Server

    Kadelka, Claus; Adeyeye, John O; Laubenbacher, Reinhard

    2014-01-01

    The concept of a nested canalizing Boolean function has been studied over the last decade in the context of understanding the regulatory logic of molecular interaction networks, such as gene regulatory networks. Such networks are predominantly governed by nested canalizing functions. Derrida values are frequently used to analyze the robustness of a Boolean network to perturbations. This paper introduces closed formulas for the calculation of Derrida values of networks governed by Boolean nested canalizing functions, which previously required extensive simulations. Recently, the concept of nested canalizing functions has been generalized to include multistate functions, and a recursive formula has been derived for their number, as a function of the number of variables. This paper contains a detailed analysis of the class of nested canalizing functions over an arbitrary finite field. In addition, the concept of nested canalization is further generalized and closed formulas for the number of such generalized fun...

  5. Influence of nonlinearities on the power output of the Self-Oscillating Fluidic Heat Engine (SOFHE)

    Science.gov (United States)

    Tessier-Poirier, A.; Monin, T.; Léveillé, E.; Formosa, F.; Monfray, S.; Fréchette, L. G.

    2016-11-01

    In this paper, it is shown that two non-linearities drive the oscillations amplitude and the potential power density of the Self-Oscillating Fluidic Heat Engine (SOFHE). This new type of engine converts thermal energy into mechanical energy by producing self-sustained oscillations of a liquid column from a continuous heat source to power wireless sensors from waste heat. The underlying theoretical modeling shows that the pressure and the temperature nonlinearities limit the final oscillations amplitude, hence its achievable power density.

  6. A High-Voltage SOI CMOS Exciter Chip for a Programmable Fluidic Processor System.

    Science.gov (United States)

    Current, K W; Yuk, K; McConaghy, C; Gascoyne, P R C; Schwartz, J A; Vykoukal, J V; Andrews, C

    2007-06-01

    A high-voltage (HV) integrated circuit has been demonstrated to transport fluidic droplet samples on programmable paths across the array of driving electrodes on its hydrophobically coated surface. This exciter chip is the engine for dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip systems, creating field excitations that inject and move fluidic droplets onto and about the manipulation surface. The architecture of this chip is expandable to arrays of N X N identical HV electrode driver circuits and electrodes. The exciter chip is programmable in several senses. The routes of multiple droplets may be set arbitrarily within the bounds of the electrode array. The electrode excitation waveform voltage amplitude, phase, and frequency may be adjusted based on the system configuration and the signal required to manipulate a particular fluid droplet composition. The voltage amplitude of the electrode excitation waveform can be set from the minimum logic level up to the maximum limit of the breakdown voltage of the fabrication technology. The frequency of the electrode excitation waveform can also be set independently of its voltage, up to a maximum depending upon the type of droplets that must be driven. The exciter chip can be coated and its oxide surface used as the droplet manipulation surface or it can be used with a top-mounted, enclosed fluidic chamber consisting of a variety of materials. The HV capability of the exciter chip allows the generated DEP forces to penetrate into the enclosed chamber region and an adjustable voltage amplitude can accommodate a variety of chamber floor thicknesses. This demonstration exciter chip has a 32 x 32 array of nominally 100 V electrode drivers that are individually programmable at each time point in the procedure to either of two phases: 0deg and 180deg with respect to the reference clock. For this demonstration chip, while operating the electrodes with a 100-V peak-to-peak periodic waveform, the maximum HV electrode

  7. Experimental design studies and flow visualization of proportional laminar-flow fluidic amplifiers

    Science.gov (United States)

    Hellbaum, R. F.; Mcdermon, J. N.

    1977-01-01

    The effects of certain parameter variations on the performance characteristics of laminar, proportional, jet-deflection fluidic amplifiers were studied. The matching and staging of amplifiers to obtain high pressure gain was included, but dynamic effects were not. The parameter variations considered were aspect ratio, setback, control length, splitter distance, receiver-duct width, width of center-vent duct, and bias pressure. Usable pressure gains of 19 per stage were achieved, and 5 amplifier stages were integrated to yield an overall pressure gain of 2,000,000.

  8. The design and function of birds' nests.

    Science.gov (United States)

    Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

    2014-10-01

    All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s.

  9. Optimal Nesting for Continuous Shape Stamping Processes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper discusses the optimal nesting problem for minimizing the scrap in continuous shape stamping processes. The shape sliding technique is used to propose a new approach, OVERLAP-and-ESCAPE, to solve the problem of continuously nesting shapes onto a metal coil of fixed or selectable width. The approach is used to construct the objective function of the mathematical model of the problem using the Simulated Annealing Algorithm to determine the globally minimal configurations for the nesting problems. Some representative cases are studied and the results are encouraging. An automatic nesting software package for manufacturing bicycle chain link blanks is also described.

  10. Nest distribution and nest habitat of the Tibetan Partridge (Perdix hodgsoniae) near Lhasa, Tibet

    Institute of Scientific and Technical Information of China (English)

    Tsering; Dorge; G?ran; H?gstedt; Terje; Lislevand

    2014-01-01

    Background: Little is hitherto known about the breeding ecology of the Tibetan Partridge(Perdix hodgsoniae)which is endemic to the Tibetan plateau. Here we describe nest densities, inter-nest distances and general nest site characteristics in this gallinaceous bird species and explore the possibilities that certain shrub and plant types are preferred as nest surroundings.Method: A total of 56 nests were found over three breeding seasons near Lhasa, Tibet. Nest site characteristics were compared with random control plots and the proportions of specific plant species covering nests were compared with their estimated general occurrence in the study area.Results: Nest density in the two years with highest search effort was estimated at 1.43/km2 and 1.04/km2 but was clearly higher in the part of the study area facing north(1.86–2.35/km2) than that facing south(0.11–0.34/ km2). The average nearest neighbour distance of nests was about 300 m. Nests were situated in relatively lush vegetation and covered by a total of eight shrub species and three herbs. In contrast to previous reports, Caragana shrub did not constitute an important part of the nest habitat. The flowering, non-thorny bush Potentilla fruticosa was significantly over-represented as nest cover, while Rhododendron nivale was similarly under-represented. Nest bush foliage covered a larger area of ground, and the shrub surrounding nests was generally denser, than in control samples. Also, nests were placed closer to paths and in areas with lower densities of Yak(Bos grunniens) dung than in control samples.Except that soil temperatures were lower on nest sites than on control sites, micro-climate variables measured in this study did not differ between nest sites and control plots.Conclusions: Opportunity for nest concealment is probably an important quality of the nest habitat in Tibetan Partridges, yet it is unclear why the species should prefer P. fruticosa as nest cover. It is possible that nest sites are

  11. Nest distribution and nest habitat of the Tibetan Partridge (Perdix hodgsoniae) near Lhasa, Tibet

    Institute of Scientific and Technical Information of China (English)

    Tsering Dorge; Gran Hgstedt; Terje Lislevand

    2014-01-01

    Background:Little is hitherto known about the breeding ecology of the Tibetan Partridge (Perdix hodgsoniae) which is endemic to the Tibetan plateau. Here we describe nest densities, inter-nest distances and general nest site characteristics in this gallinaceous bird species and explore the possibilities that certain shrub and plant types are preferred as nest surroundings. Method:A total of 56 nests were found over three breeding seasons near Lhasa, Tibet. Nest site characteristics were compared with random control plots and the proportions of specific plant species covering nests were compared with their estimated general occurrence in the study area. Results:Nest density in the two years with highest search effort was estimated at 1.43/km2 and 1.04/km2 but was clearly higher in the part of the study area facing north (1.86–2.35/km2) than that facing south (0.11–0.34/km2). The average nearest neighbour distance of nests was about 300 m. Nests were situated in relatively lush vegetation and covered by a total of eight shrub species and three herbs. In contrast to previous reports, Caragana shrub did not constitute an important part of the nest habitat. The flowering, non-thorny bush Potentil a fruticosa was significantly over-represented as nest cover, while Rhododendron nivale was similarly under-represented. Nest bush foliage covered a larger area of ground, and the shrub surrounding nests was generally denser, than in control samples. Also, nests were placed closer to paths and in areas with lower densities of Yak (Bos grunniens) dung than in control samples. Except that soil temperatures were lower on nest sites than on control sites, micro-climate variables measured in this study did not differ between nest sites and control plots. Conclusions:Opportunity for nest concealment is probably an important quality of the nest habitat in Tibetan Partridges, yet it is unclear why the species should prefer P. fruticosa as nest cover. It is possible that nest sites

  12. Nested Trampoline Resonators for Optomechanics

    CERN Document Server

    Weaver, Matthew J; Luna, Fernando; Buters, Frank M; Eerkens, Hedwig J; Welker, Gesa; Perock, Blaise; Heeck, Kier; de Man, Sven; Bouwmeester, Dirk

    2015-01-01

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating novel trampoline resonators made from low pressure chemical vapor deposition (LPCVD) Si$_3$N$_4$ with a distributed bragg reflector (DBR) mirror. We construct a nested double resonator structure that generates approximately 80 dB of mechanical isolation from the mounting surface, eliminating the strong mounting dependence of the quality factor observed with single resonators. With the consistency provided by this isolation scheme we reliably fabricate devices with mechanical quality factors of around 400,000 at room temperature. In addition these devices were used to form optical cavities with finesse up to 181,000 $\\pm$ 1,000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  13. Nested trampoline resonators for optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, M. J., E-mail: mweaver@physics.ucsb.edu; Pepper, B.; Luna, F.; Perock, B. [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Buters, F. M.; Eerkens, H. J.; Welker, G.; Heeck, K.; Man, S. de [Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, 2333 CA Leiden (Netherlands); Bouwmeester, D. [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, 2333 CA Leiden (Netherlands)

    2016-01-18

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating trampoline resonators made from low pressure chemical vapor deposition Si{sub 3}N{sub 4} with a distributed Bragg reflector mirror. We design a nested double resonator structure with 80 dB of mechanical isolation from the mounting surface at the inner resonator frequency, and we demonstrate up to 45 dB of isolation at lower frequencies in agreement with the design. We reliably fabricate devices with mechanical quality factors of around 400 000 at room temperature. In addition, these devices were used to form optical cavities with finesse up to 181 000 ± 1000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  14. 1989 Waterfowl Nesting Study and Nesting Summary 1984-1989 : Big Stone National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The 1989 nesting season marked the sixth consecutive and final year that Big Stone personnel have conducted waterfowl nesting research. In addition, an experimental...

  15. Frog Foam Nest Protein Diversity and Synthesis.

    Science.gov (United States)

    Hissa, Denise Cavalcante; Bezerra, Walderly Melgaço; Freitas, Cléverson Diniz Teixeira De; Ramos, Márcio Viana; Lopes, José Luiz De Souza; Beltramini, Leila Maria; Roberto, Igor Joventino; Cascon, Paulo; Melo, Vânia Maria Maciel

    2016-08-01

    Some amphibian species have developed a breeding strategy in which they deposit their eggs in stable foam nests to protect their eggs and larvae. The frog foam nests are rich in proteins (ranaspumin), especially surfactant proteins, involved in the production of the foam nest. Despite the ecological importance of the foam nests for evolution and species conservation, the biochemical composition, the long-term stability and even the origin of the components are still not completely understood. Recently we showed that Lv-RSN-1, a 23.5-kDa surfactant protein isolated from the nest of the frog Leptodacylus vastus, presents a structural conformation distinct from any protein structures yet reported. So, in the current study we aimed to reveal the protein composition of the foam nest of L. vastus and further characterize the Lv-RSN-1. Proteomic analysis showed the foam nest contains more than 100 of proteins, and that Lv-RSN-1 comprises 45% of the total proteins, suggesting a key role in the nest construction and stability. We demonstrated by Western blotting that Lv-RSN-1 is mainly produced only by the female in the pars convoluta dilata, which highlights the importance of the female preservation for conservation of species that depend on the production of foam nests in the early stages of development. Overall, our results showed the foam nest of L. vastus is composed of a great diversity of proteins and that besides Lv-RSN-1, the main protein in the foam, other proteins must have a coadjuvant role in building and stability of the nest.

  16. Aromatic Plants in Eurasian Blue Tit Nests: The ‘Nest

    OpenAIRE

    Pires, Bárbara A.; Anabela F. Belo; Rabaça, João E.

    2012-01-01

    The ‘Nest Protection Hypothesis’ suggests that some birds add aromatic plants to their nests to repel or kill ectoparasites. This behavior has been described for several species, including the Eurasian Blue Tit (Cyanistes caeruleus). We studied the reproductive performance, based on 26 nests (in nest boxes), of this species in mixed forested areas of Quercus spp. and Pinus pinea in the Parque Florestal de Monsanto, the largest park of Lisbon, Portugal. The frequency of aromatic plant...

  17. Florida harvester ant nest architecture, nest relocation and soil carbon dioxide gradients.

    Science.gov (United States)

    Tschinkel, Walter R

    2013-01-01

    Colonies of the Florida harvester ant, Pogonomyrmex badius, excavate species-typical subterranean nests up the 3 m deep with characteristic vertical distribution of chamber area/shape, spacing between levels and vertical arrangement of the ants by age and brood stage. Colonies excavate and occupy a new nest about once a year, and doing so requires that they have information about the depth below ground. Careful excavation and mapping of vacated and new nests revealed that there was no significant difference between the old and new nests in any measure of nest size, shape or arrangement. Colonies essentially built a replicate of the just-vacated nest (although details differed), and they did so in less than a week. The reason for nest relocation is not apparent. Tschinkel noted that the vertical distribution of chamber area, worker age and brood type was strongly correlated to the soil carbon dioxide gradient, and proposed that this gradient serves as a template for nest excavation and vertical distribution. To test this hypothesis, the carbon dioxide gradient of colonies that were just beginning to excavate a new nest was eliminated by boring 6 vent holes around the forming nest, allowing the soil CO2 to diffuse into the atmosphere and eliminating the gradient. Sadly, neither the nest architecture nor the vertical ant distribution of vented nests differed from either unvented control or from their own vacated nest. In a stronger test, workers excavated a new nest under a reversed carbon dioxide gradient (high concentration near the surface, low below). Even under these conditions, the new and old nests did not differ significantly, showing that the soil carbon dioxide gradient does not serve as a template for nest construction or vertical worker distribution. The possible importance of soil CO2 gradients for soil-dwelling animals is discussed.

  18. Proton beam writing of long, arbitrary structures for micro/nano photonics and fluidics applications

    Energy Technology Data Exchange (ETDEWEB)

    Udalagama, Chammika, E-mail: chammika@nus.edu.sg [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); Teo, E.J. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); Chan, S.F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); NUS Nanoscience and Nanotechnology Initiative, 2 Science Drive 3, 117542 (Singapore); Department of Chemistry, NUS, 3 Science Drive 3, 117543 (Singapore); Kumar, V.S.; Bettiol, A.A.; Watt, F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore)

    2011-10-15

    The last decade has seen proton beam writing maturing into a versatile lithographic technique able to produce sub-100 nm, high aspect ratio structures with smooth side walls. However, many applications in the fields of photonics and fluidics require the fabrication of structures with high spatial resolution that extends over several centimetres. This cannot be achieved by purely magnetic or electrostatic beam scanning due to the large off-axis beam aberrations in high demagnification systems. As a result, this has limited us to producing long straight structures using a combination of beam and stage scanning. In this work we have: (1) developed an algorithm to include any arbitrary pattern into the writing process by using a more versatile combination of beam and stage scanning while (2) incorporating the use of the ubiquitous AutoCAD DXF (drawing exchange format) into the design process. We demonstrate the capability of this approach in fabricating structures such as Y-splitters, Mach-Zehnder modulators and microfluidic channels that are over several centimetres in length, in polymer. We also present optimisation of such parameters as scanning speed and scanning loops to improve on the surface roughness of the structures. This work opens up new possibilities of using CAD software in PBW for microphotonics and fluidics device fabrication.

  19. The smart Peano fluidic muscle: a low profile flexible orthosis actuator that feels pain

    Science.gov (United States)

    Veale, Allan J.; Anderson, Iain A.; Xie, Shane Q.

    2015-03-01

    Robotic orthoses have the potential to provide effective rehabilitation while overcoming the availability and cost constraints of therapists. These orthoses must be characterized by the naturally safe, reliable, and controlled motion of a human therapist's muscles. Such characteristics are only possible in the natural kingdom through the pain sensing realized by the interaction of an intelligent nervous system and muscles' embedded sensing organs. McKibben fluidic muscles or pneumatic muscle actuators (PMAs) are a popular orthosis actuator because of their inherent compliance, high force, and muscle-like load-displacement characteristics. However, the circular cross-section of PMA increases their profile. PMA are also notoriously unreliable and difficult to control, lacking the intelligent pain sensing systems of their biological muscle counterparts. Here the Peano fluidic muscle, a new low profile yet high-force soft actuator is introduced. This muscle is smart, featuring bioinspired embedded pressure and soft capacitive strain sensors. Given this pressure and strain feedback, experimental validation shows that a lumped parameter model based on the muscle geometry and material parameters can be used to predict its force for quasistatic motion with an average error of 10 - 15N. Combining this with a force threshold pain sensing algorithm sets a precedent for flexible orthosis actuation that uses embedded sensors to prevent damage to the actuator and its environment.

  20. Methodology for designing and manufacturing complex biologically inspired soft robotic fluidic actuators: prosthetic hand case study.

    Science.gov (United States)

    Thompson-Bean, E; Das, R; McDaid, A

    2016-10-31

    We present a novel methodology for the design and manufacture of complex biologically inspired soft robotic fluidic actuators. The methodology is applied to the design and manufacture of a prosthetic for the hand. Real human hands are scanned to produce a 3D model of a finger, and pneumatic networks are implemented within it to produce a biomimetic bending motion. The finger is then partitioned into material sections, and a genetic algorithm based optimization, using finite element analysis, is employed to discover the optimal material for each section. This is based on two biomimetic performance criteria. Two sets of optimizations using two material sets are performed. Promising optimized material arrangements are fabricated using two techniques to validate the optimization routine, and the fabricated and simulated results are compared. We find that the optimization is successful in producing biomimetic soft robotic fingers and that fabrication of the fingers is possible. Limitations and paths for development are discussed. This methodology can be applied for other fluidic soft robotic devices.

  1. Characterization of a tunable astigmatic fluidic lens with adaptive optics correction for compact phoropter application

    Science.gov (United States)

    Fuh, Yiin-Kuen; Huang, Chieh-Tse

    2014-07-01

    Fluidically controlled lenses which adaptively correct prescribed refractive error without mechanically moving parts are extensively applied in the ophthalmic applications. Capable of variable-focusing properties, however, the associated aberrations due to curvature change and refractive index mismatch can inherently degrade image quality severely. Here we present the experimental study of the aberrations in tunable astigmatic lens and use of adaptive optics to compensate for the wavefront errors. Characterization of the optical properties of the individual lenses is carried out by Shack-Hartmann measurements. An adaptive optics (AO) based scheme is demonstrated for three injected fluidic volumes, resulting in a substantial reduction of the wavefront errors from -0.12, -0.25, -0.32 to 0.01, -0.01, -0.20 μm, respectively, corresponding to the optical power tenability of 0.83 to 1.84 D. Furthermore, an integrated optical phoroptor consisting of adjustable astigmatic lenses and AO correction is demonstrated such that an induced refraction error of -1 D cylinder at 180° of a model eye vision is experimentally corrected.

  2. Fluidic Logic Used in a Systems Approach to Enable Integrated Single-cell Functional Analysis

    Directory of Open Access Journals (Sweden)

    Naveen Ramalingam

    2016-09-01

    Full Text Available The study of single cells has evolved over the past several years to include expression and genomic analysis of an increasing number of single cells. Several studies have demonstrated wide-spread variation and heterogeneity within cell populations of similar phenotype. While the characterization of these populations will likely set the foundation for our understanding of genomic- and expression-based diversity, it will not be able to link the functional differences of a single cell to its underlying genomic structure and activity. Currently, it is difficult to perturb single cells in a controlled environment, monitor and measure the response due to perturbation, and link these response measurements to downstream genomic and transcriptomic analysis. In order to address this challenge, we developed a platform to integrate and miniaturize many of the experimental steps required to study single-cell function. The heart of this platform is an elastomer-based Integrated Fluidic Circuit (IFC that uses fluidic logic to select and sequester specific single cells based on a phenotypic trait for downstream experimentation. Experiments with sequestered cells that have been performed include on-chip culture, exposure to a variety of stimulants, and post-exposure image-based response analysis, followed by preparation of the mRNA transcriptome for massively parallel sequencing analysis. The flexible system embodies experimental design and execution that enable routine functional studies of single cells.

  3. Ultrathin Fluidic Laminates for Large-Area Façade Integration and Smart Windows.

    Science.gov (United States)

    Heiz, Benjamin P V; Pan, Zhiwen; Lautenschläger, Gerhard; Sirtl, Christin; Kraus, Matthias; Wondraczek, Lothar

    2017-03-01

    Buildings represent more than 40% of Europe's energy demands and about one third of its CO2 emissions. Energy efficient buildings and, in particular, building skins have therefore been among the key priorities of international research agendas. Here, glass-glass fluidic devices are presented for large-area integration with adaptive façades and smart windows. These devices enable harnessing and dedicated control of various liquids for added functionality in the building envelope. Combining a microstructured glass pane, a thin cover sheet with tailored mechanical performance, and a liquid for heat storage and transport, a flat-panel laminate is generated with thickness adapted to a single glass sheet in conventional windows. Such multimaterial devices can be integrated with state-of-the-art window glazings or façades to harvest and distribute thermal as well as solar energy by wrapping buildings into a fluidic layer. High visual transparency is achieved through adjusting the optical properties of the employed liquid. Also secondary functionality, such as chromatic windows, polychromatism, or adaptive energy uptake can be generated on part of the liquid.

  4. On-demand frequency tunability of fluidic antenna implemented with gallium-based liquid metal alloy

    Science.gov (United States)

    Kim, Daeyoung; Doo, Seok Joo; Won, Heong Sup; Lee, Woojin; Jeon, Jinpyo; Chung, Sang Kug; Lee, Gil-Young; Oh, Semyoung; Lee, Jeong-Bong

    2017-04-01

    We investigated frequency tunability of a microfluidic-based antenna using on-demand manipulation of a gallium-based liquid metal alloy. The fluidic antenna was fabricated by polydimethylsiloxane (PDMS) and filled with the gallium-based liquid metal alloy (Galinstan®). It is composed of a digital number "7"-shaped feedline, and a square-shaped and a digital number "6"-shaped patterns, which are all implemented with the liquid metal. The gallium-based liquid metal was adhered to the channel surface due to its viscous oxide layer originating from the gallium oxide forming when it exposed to the air environment. We treated the liquid metal with hydrochloric acid solution to remove the oxide layer on the surface resulting in easy movement of the liquid metal in the channel, as the liquid metal surface has been transformed to be non-wettable. We controlled the physical length of the liquid metal slug filled in feedline with an applied air pressure, resulting in tuning the resonant frequency ranging from 2.2 GHz to 9.3 GHz. The fluidic antenna properties using the liquid metal's electrical conductivity and mobility were characterized by measuring the return loss (S11), and also simulated with CST Microwave Studio.

  5. Fabrication of Biochips with Micro Fluidic Channels by Micro End-milling and Powder Blasting

    Directory of Open Access Journals (Sweden)

    Dong Sam Park

    2008-02-01

    Full Text Available For microfabrications of biochips with micro fluidic channels, a large number of microfabrication techniques based on silicon or glass-based Micro-Electro-Mechanical System (MEMS technologies were proposed in the last decade. In recent years, for low cost and mass production, polymer-based microfabrication techniques by microinjection molding and micro hot embossing have been proposed. These techniques, which require a proper photoresist, mask, UV light exposure, developing, and electroplating as a preprocess, are considered to have some problems. In this study, we propose a new microfabrication technology which consists of micro end-milling and powder blasting. This technique could be directly applied to fabricate the metal mold without any preprocesses. The metal mold with micro-channels is machined by micro end-milling, and then, burrs generated in the end-milling process are removed by powder blasting. From the experimental results, micro end-milling combined with powder blasting could be applied effectively for fabrication of the injection mold of biochips with micro fluidic channels.

  6. Thermo-fluidic devices and materials inspired from mass and energy transport phenomena in biological system

    Institute of Scientific and Technical Information of China (English)

    Jian XIAO; Jing LIU

    2009-01-01

    Mass and energy transport consists of one of the most significant physiological processes in nature, which guarantees many amazing biological phenomena and activ-ities. Borrowing such idea, many state-of-the-art thermo-fluidic devices and materials such as artificial kidneys, carrier erythrocyte, blood substitutes and so on have been successfully invented. Besides, new emerging technologies are still being developed. This paper is dedicated to present-ing a relatively complete review of the typical devices and materials in clinical use inspired by biological mass and energy transport mechanisms. Particularly, these artificial thermo-fluidic devices and materials will be categorized into organ transplantation, drug delivery, nutrient transport, micro operation, and power supply. Potential approaches for innovating conventional technologies were discussed, corresponding biological phenomena and physical mechan-isms were interpreted, future promising mass-and-energy-transport-based bionic devices were suggested, and prospects along this direction were pointed out. It is expected that many artificial devices based on biological mass and energy transport principle will appear to better improve vari-ous fields related to human life in the near future.

  7. Modeling and testing of a knitted-sleeve fluidic artificial muscle

    Science.gov (United States)

    Ball, Erick J.; Meller, Michael A.; Chipka, Jordan B.; Garcia, Ephrahim

    2016-11-01

    The knitted-sleeve fluidic muscle is similar in design to a traditional McKibben muscle, with a separate bladder and sleeve. However, in place of a braided sleeve, it uses a tubular-knit sleeve made from a thin strand of flexible but inextensible yarn. When the bladder is pressurized, the sleeve expands by letting the loops of fiber slide past each other, changing the dimensions of the rectangular cells in the stitch pattern. Ideally, the internal volume of the sleeve would reach a maximum when its length has contracted by 2/3 from its maximum length, and although this is not reachable in practice, preliminary tests show that free contraction greater than 50% is achievable. The motion relies on using a fiber with a low coefficient of friction in order to reduce hysteresis to an acceptable level. In addition to increased stroke length, potential advantages of this technique include slower force drop-off during the stroke, more useable energy in certain applications, and greater similarity to the force-length relationship of skeletal muscle. Its main limitation is its potentially greater effect from friction compared to other fluidic muscle designs.

  8. Porous PDMS structures for the storage and release of aqueous solutions into fluidic environments.

    Science.gov (United States)

    Thurgood, Peter; Baratchi, Sara; Szydzik, Crispin; Mitchell, Arnan; Khoshmanesh, Khashayar

    2017-07-11

    Typical microfluidic systems take advantage of multiple storage reservoirs, pumps and valves for the storage, driving and release of buffers and other reagents. However, the fabrication, integration, and operation of such components can be difficult. In particular, the reliance of such components on external off-chip equipment limits their utility for creating self-sufficient, stand-alone microfluidic systems. Here, we demonstrate a porous sponge made of polydimethylsiloxane (PDMS), which is fabricated by templating microscale water droplets using a T-junction microfluidic structure. High-resolution microscopy reveals that this sponge contains a network of pores, interconnected by small holes. This unique structure enables the sponge to passively release stored solutions very slowly. Proof-of-concept experiments demonstrate that the sponge can be used for the passive release of stored solutions into narrow channels and circular well plates, with the latter used for inducing intracellular calcium signalling of immobilised endothelial cells. The release rate of stored solutions can be controlled by varying the size of interconnecting holes, which can be easily achieved by changing the flow rate of the water injected into the T-junction. We also demonstrate the active release of stored liquids into a fluidic channel upon the manual compression of the sponge. The developed PDMS sponge can be easily integrated into complex micro/macro fluidic systems and prepared with a wide array of reagents, representing a new building block for self-sufficient microfluidic systems.

  9. Computational Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for a Supersonic Aircraft Application

    Science.gov (United States)

    Deere, Karen A.; Flamm, Jeffrey D.; Berrier, Bobby L.; Johnson, Stuart K.

    2007-01-01

    A computational investigation of an axisymmetric Dual Throat Nozzle concept has been conducted. This fluidic thrust-vectoring nozzle was designed with a recessed cavity to enhance the throat shifting technique for improved thrust vectoring. The structured-grid, unsteady Reynolds- Averaged Navier-Stokes flow solver PAB3D was used to guide the nozzle design and analyze performance. Nozzle design variables included extent of circumferential injection, cavity divergence angle, cavity length, and cavity convergence angle. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 1.89 to 10, with the fluidic injection flow rate equal to zero and up to 4 percent of the primary flow rate. The effect of a variable expansion ratio on nozzle performance over a range of freestream Mach numbers up to 2 was investigated. Results indicated that a 60 circumferential injection was a good compromise between large thrust vector angles and efficient internal nozzle performance. A cavity divergence angle greater than 10 was detrimental to thrust vector angle. Shortening the cavity length improved internal nozzle performance with a small penalty to thrust vector angle. Contrary to expectations, a variable expansion ratio did not improve thrust efficiency at the flight conditions investigated.

  10. Chapter 6: Characteristics of Marbled Murrelet Nest Trees and Nesting Stands

    Science.gov (United States)

    Thomas E. Hamer; S. Kim Nelson

    1995-01-01

    We summarize the characteristics of 61 tree nests and nesting stands of the Marbled Murrelet ( Brachyramphus marmoratus ) located from 1974 to 1993 in Alaska, British Columbia, Washington, Oregon, and California. Evidence of breeding 30-60 km inland was common in California, Oregon, and Washington. Nesting greater distances from the coast may have...

  11. Landscape forest cover and edge effects on songbird nest predation vary by nest predator

    Science.gov (United States)

    W. Andrew Cox; Frank R. III Thompson; John. Faaborg

    2012-01-01

    Rates of nest predation for birds vary between and within species across multiple spatial scales, but we have a poor understanding of which predators drive such patterns. We video-monitored nests and identified predators at 120 nests of the Acadian Flycatcher (Empidonax virescens) and the Indigo Bunting (Passerina cyanea) at eight...

  12. Waterbird nest-site selection is influenced by neighboring nests and island topography

    Science.gov (United States)

    Hartman, Christopher; Ackerman, Josh; Takekawa, John Y.; Herzog, Mark

    2016-01-01

    Avian nest-site selection is influenced by factors operating across multiple spatial scales. Identifying preferred physical characteristics (e.g., topography, vegetation structure) can inform managers to improve nesting habitat suitability. However, social factors (e.g., attraction, territoriality, competition) can complicate understanding physical characteristics preferred by nesting birds. We simultaneously evaluated the physical characteristics and social factors influencing selection of island nest sites by colonial-nesting American avocets (Recurvirostra americana) and Forster's terns (Sterna forsteri) at 2 spatial scales in San Francisco Bay, 2011–2012. At the larger island plot (1 m2) scale, we used real-time kinematics to produce detailed topographies of nesting islands and map the distribution of nests. Nesting probability was greatest in island plots between 0.5 m and 1.5 m above the water surface, at distances less likely to nest in plots adjacent to plots with nesting avocets, suggesting an influence of intra-specific territoriality. At the smaller microhabitat scale, or the area immediately surrounding the nest, we compared topography, vegetation, and distance to nearest nest between nest sites and paired random sites. Topography had little influence on selection of the nest microhabitat. Instead, nest sites were more likely to have vegetation present, and greater cover, than random sites. Finally, avocet, and to a lesser extent tern, nest sites were closer to other active conspecific or heterospecific nests than random sites, indicating that social attraction played a role in selection of nest microhabitat. Our results demonstrate key differences in nest-site selection between co-occurring avocets and terns, and indicate the effects of physical characteristics and social factors on selection of nesting habitat are dependent on the spatial scale examined. Moreover, these results indicate that islands with abundant area between 0.5 m and 1.5

  13. Conservation significance of alternative nests of golden eagles

    Directory of Open Access Journals (Sweden)

    Brian A. Millsap

    2015-01-01

    Full Text Available Golden eagles (Aquila chrysaetos are long-lived raptors that maintain nesting territories that may be occupied for a century or longer. Within occupied nesting territories there is one nest in which eagles lay their eggs in a given year (i.e., the used nest, but there are usually other nests (i.e., alternative nests. Conservation plans often protect used nests, but not alternative nests or nesting territories that appear vacant. Our objective is to review literature on golden eagle use of alternative nests and occupancy of nesting territories to determine if alternative nests are biologically significant and warrant greater conservation consideration. Our review shows that: (1 alternative nests or their associated habitat are most often in core areas of golden eagle nesting territories; (2 alternative nests likely will become used in the future; (3 probability of an alternative nest becoming used is greatest where prey availability is high and alternative nest sites are limited; (4 likelihood of annual occupancy or reoccupancy of golden eagle nesting territories is high; and (5 prey availability is the most important determinant of nesting territory occupancy and breeding activity. We recommend alternative nests be treated with the same deference as used nests in land use planning.

  14. 7 CFR 29.6027 - Nested.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Nested. 29.6027 Section 29.6027 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6027 Nested. Any tobacco which has been loaded, packed, or arranged...

  15. Dune vegetation fertilization by nesting sea turtles.

    Science.gov (United States)

    Hannan, Laura B; Roth, James D; Ehrhart, Llewellyn M; Weishampel, John F

    2007-04-01

    Sea turtle nesting presents a potential pathway to subsidize nutrient-poor dune ecosystems, which provide the nesting habitat for sea turtles. To assess whether this positive feedback between dune plants and turtle nests exists, we measured N concentration and delta15N values in dune soils, leaves from a common dune plant (sea oats [Uniola paniculata]), and addled eggs of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) across a nesting gradient (200-1050 nests/km) along a 40.5-km stretch of beach in east central Florida, USA. The delta15N levels were higher in loggerhead than green turtle eggs, denoting the higher trophic level of loggerhead turtles. Soil N concentration and delta15N values were both positively correlated to turtle nest density. Sea oat leaf tissue delta15N was also positively correlated to nest density, indicating an increased use of augmented marine-based nutrient sources. Foliar N concentration was correlated with delta15N, suggesting that increased nutrient availability from this biogenic vector may enhance the vigor of dune vegetation, promoting dune stabilization and preserving sea turtle nesting habitat.

  16. Freeform fluidics

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R; Lind, Randall F; Love, Lonnie L; Peter, William H; Richardson, Bradley S

    2015-02-10

    A robotic, prosthetic or orthotic member includes a body formed of a solidified metallic powder. At least one working fluid cylinder is formed in the body. A piston is provided in the working fluid cylinder for pressurizing a fluid in the cylinder. At least one working fluid conduit receives the pressurized fluid from the cylinder. The body, working fluid cylinder and working fluid conduit have a unitary construction. A method of making a robotic member is also disclosed.

  17. Developing and Analysing sub-10 µm Fluidic Systems with Integrated Electrodes for Pumping and Sensing in Nanotechnology Applications

    NARCIS (Netherlands)

    Heuck, F.C.A.

    2010-01-01

    In this thesis, sub-10 µm fluidic systems with integrated electrodes for pumping and sensing in nanotechnology applications were developed and analyzed. This work contributes to the development of the scanning ion pipette (SIP), a tool to investigate surface changes on the nanometer scale induced by

  18. Developing and Analysing sub-10 µm Fluidic Systems with Integrated Electrodes for Pumping and Sensing in Nanotechnology Applications

    NARCIS (Netherlands)

    Heuck, F.C.A.

    2010-01-01

    In this thesis, sub-10 µm fluidic systems with integrated electrodes for pumping and sensing in nanotechnology applications were developed and analyzed. This work contributes to the development of the scanning ion pipette (SIP), a tool to investigate surface changes on the nanometer scale induced by

  19. Development of a millimetrically scaled biodiesel transesterification device that relies on droplet-based co-axial fluidics

    Science.gov (United States)

    Yeh, S. I.; Huang, Y. C.; Cheng, C. H.; Cheng, C. M.; Yang, J. T.

    2016-07-01

    In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here – soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world.

  20. Investigation of the dye concentration influence on the lasing wavelength and threshold for a micro-fluidic dye laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kragh, Søren; Kjeldsen, B.G.;

    2003-01-01

    We investigate a micro-fluidic dye laser, which can be integrated with polymer-based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the lasing threshold. The laser device is characterised using the laser dye Rhodamine 6G dissolved in e...

  1. Low-cost technology for the integration of micro- and nanochips into fluidic systems on printed circuit board: fabrication challenges

    NARCIS (Netherlands)

    Palacios-Aguilera, N.B.; Bastemeijer, J.; Mollinger, J.R.; Bossche, A.; Mokkapati, V.R.S.S.; Visser, Roy; Akkerman, Remko

    2012-01-01

    Nowadays, micro- and nanochips are usually fabricated with Silicon and/or glass. A simple, low-cost and reliable integration packaging method that provides flexibility to the incorporation of electronic and fluidic devices into a system has not been fully developed yet. The use of Printed Circuit

  2. Automated Forensic Animal Family Identification by Nested PCR and Melt Curve Analysis on an Off-the-Shelf Thermocycler Augmented with a Centrifugal Microfluidic Disk Segment.

    Directory of Open Access Journals (Sweden)

    Mark Keller

    Full Text Available Nested PCR remains a labor-intensive and error-prone biomolecular analysis. Laboratory workflow automation by precise control of minute liquid volumes in centrifugal microfluidic Lab-on-a-Chip systems holds great potential for such applications. However, the majority of these systems require costly custom-made processing devices. Our idea is to augment a standard laboratory device, here a centrifugal real-time PCR thermocycler, with inbuilt liquid handling capabilities for automation. We have developed a microfluidic disk segment enabling an automated nested real-time PCR assay for identification of common European animal groups adapted to forensic standards. For the first time we utilize a novel combination of fluidic elements, including pre-storage of reagents, to automate the assay at constant rotational frequency of an off-the-shelf thermocycler. It provides a universal duplex pre-amplification of short fragments of the mitochondrial 12S rRNA and cytochrome b genes, animal-group-specific main-amplifications, and melting curve analysis for differentiation. The system was characterized with respect to assay sensitivity, specificity, risk of cross-contamination, and detection of minor components in mixtures. 92.2% of the performed tests were recognized as fluidically failure-free sample handling and used for evaluation. Altogether, augmentation of the standard real-time thermocycler with a self-contained centrifugal microfluidic disk segment resulted in an accelerated and automated analysis reducing hands-on time, and circumventing the risk of contamination associated with regular nested PCR protocols.

  3. Development of Two Color Fluorescent Imager and Integrated Fluidic System for Nanosatellite Biology Applications

    Science.gov (United States)

    Wu, Diana Terri; Ricco, Antonio Joseph; Lera, Matthew P.; Timucin, Linda R.; Parra, Macarena P.

    2012-01-01

    Nanosatellites offer frequent, low-cost space access as secondary payloads on launches of larger conventional satellites. We summarize the payload science and technology of the Microsatellite in-situ Space Technologies (MisST) nanosatellite for conducting automated biological experiments. The payload (two fused 10-cm cubes) includes 1) an integrated fluidics system that maintains organism viability and supports growth and 2) a fixed-focus imager with fluorescence and scattered-light imaging capabilities. The payload monitors temperature, pressure and relative humidity, and actively controls temperature. C. elegans (nematode, 50 m diameter x 1 mm long) was selected as a model organism due to previous space science experience, its completely sequenced genome, size, hardiness, and the variety of strains available. Three strains were chosen: two green GFP-tagged strains and one red tdTomato-tagged strain that label intestinal, nerve, and pharyngeal cells, respectively. The integrated fluidics system includes bioanalytical and reservoir modules. The former consists of four 150 L culture wells and a 4x5 mm imaging zone the latter includes two 8 mL fluid reservoirs for reagent and waste storage. The fluidic system is fabricated using multilayer polymer rapid prototyping: laser cutting, precision machining, die cutting, and pressure-sensitive adhesives it also includes eight solenoid-operated valves and one mini peristaltic pump. Young larval-state (L2) nematodes are loaded in C. elegans Maintenance Media (CeMM) in the bioanalytical module during pre-launch assembly. By the time orbit is established, the worms have grown to sufficient density to be imaged and are fed fresh CeMM. The strains are pumped sequentially into the imaging area, imaged, then pumped into waste. Reagent storage utilizes polymer bags under slight pressure to prevent bubble formation in wells or channels. The optical system images green and red fluorescence bands by excitation with blue (473 nm peak

  4. Dinosaurs nesting on a red beach?

    Science.gov (United States)

    Sander, P. Martin; Peitz, Christian; Gallemi, Jaume; Cousin, Rémi

    1998-07-01

    The Upper Cretaceous Basturs locality (Tremp Basin, northern Spain) preserves numerous dinosaur eggs ( Megaloolithus cf. M. mammilare Vianey-Liaud, 1994). The locality was recently studied by Sanz et al. (1995) as well as by us. However, we have to disagree with several conclusions by Sanz et al. and suggest alternative interpretations incorporating data from other localities (Coll de Nargó). The dinosaurs at Basturs did not nest at the beach, nor is there evidence for colonial nesting and territorial behaviour. However, the locality superbly documents nesting site fidelity with an estimated occupation time of over 10 000 years.

  5. Emperor penguins nesting on Inaccessible Island

    Science.gov (United States)

    Jonkel, G.M.; Llano, G.A.

    1975-01-01

    Emperor penguins were observed nesting on Inaccessible I. during the 1973 winter. This is the southernmost nesting of emperor penguins thus far recorded; it also could be the first record of emperors attempting to start a new rookery. This site, however, may have been used by emperors in the past. The closest reported nesting of these penguins to Inaccessible I. is on the Ross Ice Shelf east of Cape Crozier. With the exception of the Inaccessible I. record, there is little evidence that emperor penguins breed in McMurdo Sound proper.

  6. 1988 Duck nesting study: Stillwater Wildlife Management Area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — During the summer, 1988, we conducted a duck nesting study to determine nest success for ducks at Stillwater Wildlife Management Area (WMA). We calculated nest...

  7. Nest site characteristics and nesting success of the Western Burrowing Owl in the eastern Mojave Desert

    Science.gov (United States)

    Longshore, Kathleen M.; Crowe, Dorothy E.

    2013-01-01

    We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species.

  8. The nest as fortress: Defensive behavior of Polybia emaciata, a mud-nesting eusocial wasp

    Directory of Open Access Journals (Sweden)

    Sean O'Donnell

    2002-02-01

    Full Text Available The swarm-founding wasp Polybia emaciata is unusual among eusocial Vespidae because it uses mud, rather than wood pulp, as its primary nest construction material. Polybia emaciata nests are more durable than similarly sized paper nests. We tested the hypothesis that the defensive behavior of this wasp may have been modified to take advantage of their strong nests in defense against vertebrate attacks. We simulated vertebrate disturbances by tapping on, and breathing in, P. emaciata. nests and similarly sized P. occidentalis paper nests in the same location at the same time. Polybia emaciata. responses to disturbance were qualitatively different from those of P. occidentalis. The latter exit the nest and attack, while P. emaciata. workers typically fled or entered the nest, attacking only after repeated and extended disturbances. We conclude that durable nest material may permit predator avoidance behavior in P. emaciata.. We compare the defensive responses of P. emaciata. workers with those of other swarm-founding Vespidae, and discuss several selective forces that could cause the evolution of species variation in nest defense behavior.

  9. Estimating stage-specific daily survival probabilities of nests when nest age is unknown

    Science.gov (United States)

    Stanley, T.R.

    2004-01-01

    Estimation of daily survival probabilities of nests is common in studies of avian populations. Since the introduction of Mayfield's (1961, 1975) estimator, numerous models have been developed to relax Mayfield's assumptions and account for biologically important sources of variation. Stanley (2000) presented a model for estimating stage-specific (e.g. incubation stage, nestling stage) daily survival probabilities of nests that conditions on “nest type” and requires that nests be aged when they are found. Because aging nests typically requires handling the eggs, there may be situations where nests can not or should not be aged and the Stanley (2000) model will be inapplicable. Here, I present a model for estimating stage-specific daily survival probabilities that conditions on nest stage for active nests, thereby obviating the need to age nests when they are found. Specifically, I derive the maximum likelihood function for the model, evaluate the model's performance using Monte Carlo simulations, and provide software for estimating parameters (along with an example). For sample sizes as low as 50 nests, bias was small and confidence interval coverage was close to the nominal rate, especially when a reduced-parameter model was used for estimation.

  10. Spatial dynamics of nesting behavior: lizards shift microhabitats to construct nests with beneficial thermal properties.

    Science.gov (United States)

    Angilletta, Michael J; Sears, Michael W; Pringle, Robert M

    2009-10-01

    Because temperature affects the growth, development, and survival of embryos, oviparous mothers should discriminate carefully among available nesting sites. We combined a radiotelemetric study of animal movements with a spatial mapping of environmental temperatures to test predictions about the nesting behavior of the eastern fence lizard (Sceloporus undulatus). Females made large excursions from their typical home ranges to construct nests in exposed substrates. These excursions appeared to be related solely to nesting because all females returned to forested habitat immediately afterward. On average, <1% (range = 0-8%, n = 19) of the area used by a female during nesting was contained within the area used before and after nesting. The selection of nesting sites matched predictions based on laboratory studies of embryonic performance; specifically, females nested in extremely open habitat at a mean of 6 cm depth. Spatial mapping of soil temperatures revealed that temperatures of nesting areas exceeded those of areas typically used by females, indicating that females preferred to construct warm nests that speed embryonic growth and development. However, this behavior could reduce the survivorship of females because of the need to rapidly navigate unfamiliar and exposed terrain.

  11. Construction patterns of birds’ nests provide insight into nest-building behaviours

    Science.gov (United States)

    Goodman, Adrian M.

    2017-01-01

    Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula) nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process. PMID:28265501

  12. Construction patterns of birds’ nests provide insight into nest-building behaviours

    Directory of Open Access Journals (Sweden)

    Lucia Biddle

    2017-02-01

    Full Text Available Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

  13. A variable transverse stiffness sandwich structure using fluidic flexible matrix composites (F2MC)

    Science.gov (United States)

    Li, Suyi; Lotfi, Amir; Shan, Ying; Wang, K. W.; Rahn, Christopher D.; Bakis, Charles E.

    2008-03-01

    Presented in this paper is the development of a novel honeycomb sandwich panel with variable transverse stiffness. In this structure, the traditional sandwich face sheets are replaced by the fluidic flexible matrix composite (F2MC) tube layers developed in recent studies. The F2MC layers, combined with the anisotropic honeycomb core material properties, provide a new sandwich structure with variable stiffness properties for transverse loading. In this research, an analytical model is derived based on Lekhitskii's anisotropic pressurized tube solution and Timoshenko beam theory. Experimental investigations are also conducted to verify the analytical findings. A segmented multiple-F2MC-tube configuration is synthesized to increase the variable stiffness range. The analysis shows that the new honeycomb sandwich structure using F2MC tubes of 10 segments can provide a high/low transverse stiffness ratio of 60. Segmentation and stiffness control can be realized by an embedded valve network, granting a fast response time.

  14. Variable stiffness actuator based on fluidic flexible matrix composites and piezoelectric-hydraulic pump

    Science.gov (United States)

    Kim, Gi-Woo; Li, Suyi; Wang, K. W.

    2010-04-01

    Recently, a new biological-inspired fluidic flexible matrix composite (in short, F2MC) concept has been developed for linear/torsional actuation and structural stiffness tailoring. Although the actuation and the variable stiffness features of the F2MC have been successfully demonstrated individually, their combined functions and full potentials were not yet manifested. In addition, the current hydraulic pressurization systems are bulky and heavy, limiting the potential of the F2MC actuator. To address these issues, we synthesize a new variable stiffness actuator concept that can provide both effective actuation and tunable stiffness (dual-mode), incorporating the F2MC with a compact piezoelectric-hydraulic pump (in short, PHP). This dual-mode mechanism will significantly enhance the potential of the F2MC adaptive structures.

  15. Design and testing of micro fluidic chemical analysis chip integrated with micro valveless pump

    Institute of Scientific and Technical Information of China (English)

    FU; Xin; XIE; Haibo; YANG; Huayong; JIA; Zhijian; FANG; Qun

    2005-01-01

    A new structure and working principle of the chip integrated with micro valveless pump for capillary electrophoresis was proposed in this paper. The micro valveless pump with plane structure has advantages of simple structure, and the process technology is compatible with existing micro chips for capillary electrophoresis. Based upon the mathematical model, simulation study of micro pump was carried out to investigate the influence of structural parameters on flow characteristics, and the performance of the integrated micro pump was also tested with different control parameters. The simulation results agree with the experimental results. Three samples, which are amino acid, fluorescein and buffer solution, have been examined with this chip. The results of the primary experiments showed that the micro valveless pump was promising in the integration and automatization of miniature integrated fluidic systems.

  16. Designing deoxidation inhibiting encapsulation of metal oxide nanostructures for fluidic and biological applications

    Science.gov (United States)

    Ghosh, Moumita; Ghosh, Siddharth; Seibt, Michael; Schaap, Iwan A. T.; Schmidt, Christoph F.; Mohan Rao, G.

    2016-12-01

    Due to their photoluminescence, metal oxide nanostructures such as ZnO nanostructures are promising candidates in biomedical imaging, drug delivery and bio-sensing. To apply them as label for bio-imaging, it is important to study their structural stability in a bio-fluidic environment. We have explored the effect of water, the main constituent of biological solutions, on ZnO nanostructures with scanning electron microscopy (SEM) and photoluminescence (PL) studies which show ZnO nanorod degeneration in water. In addition, we propose and investigate a robust and inexpensive method to encapsulate these nanostructures (without structural degradation) using bio-compatible non-ionic surfactant in non-aqueous medium, which was not reported earlier. This new finding is an immediate interest to the broad audience of researchers working in biophysics, sensing and actuation, drug delivery, food and cosmetics technology, etc.

  17. Silicon micro-fluidic cooling for NA62 GTK pixel detectors

    CERN Document Server

    Romagnoli, G; Brunel, B; Catinaccio, A; Degrange, J; Mapelli, A; Morel, M; Noel, J; Petagna, P

    2015-01-01

    Silicon micro-channel cooling is being studied for efficient thermal management in application fields such as high power computing and 3D electronic integration. This concept has been introduced in 2010 for the thermal management of silicon pixel detectors in high energy physics experiments. Combining the versatility of standard micro-fabrication processes with the high thermal efficiency typical of micro-fluidics, it is possible to produce effective thermal management devices that are well adapted to different detector configurations. The production of very thin cooling devices in silicon enables a minimization of material of the tracking sensors and eliminates mechanical stresses due to the mismatch of the coefficient of thermal expansion between detectors and cooling systems. The NA62 experiment at CERN will be the first high particle physics experiment that will install a micro-cooling system to perform the thermal management of the three detection planes of its Gigatracker pixel detector.

  18. Fundamental Study on New Micro Fluidic Drive Method Based on Liquid Crystalline Backflow

    Directory of Open Access Journals (Sweden)

    Chunbo Liu

    2012-11-01

    Full Text Available In this study, we propose a one-dimensional simple model for predicting the performance of the new micro fluidic drive and then we have a research of the control method based on liquid crystalline backflow by combining the motion of the upper plate of a liquid crystal cell and the flow of a liquid crystal. Comparison of the numerical predictions and the experimental results shows that the proposed model is useful to predict qualitatively the motion the upper plate. The drive efficiency is affected by applied voltage, the frequency, the duty ratio and the gap of the cell. The ideal drive quality can be achieved when the rotation range of the molecules at the center of the cell is controlled within 50-80°.

  19. Modelling the nonlinear response of fibre-reinforced bending fluidic actuators

    Science.gov (United States)

    Cacucciolo, Vito; Renda, Federico; Poccia, Ernesto; Laschi, Cecilia; Cianchetti, Matteo

    2016-10-01

    Soft actuators are receiving increasing attention from the engineering community, not only in research but even for industrial applications. Among soft actuators, fibre-reinforced bending fluidic actuators (BFAs) became very popular thanks to features such as robustness and easy design and fabrication. However, an accurate modelling of these smart structures, taking into account all the nonlinearities involved, is a challenging task. In this effort, we propose an analytical mechanical model to capture the quasi-static response of fibre-reinforced BFAs. The model is fully 3D and for the first time includes the effect of the pressure on the lateral surface of the chamber as well as the non-constant torque produced by the pressure at the tip. The presented model can be used for design and control, while providing information about the mechanics of these complex actuators.

  20. On the applicability of fluidic flexible matrix composite variable impedance materials for prosthetic and orthotic devices

    Science.gov (United States)

    Philen, M.

    2009-10-01

    The applicability of variable impedance fluidic flexible matrix composites (F2MC) is investigated for development of prosthetic and orthotic devices. The F2MC material is an innovative combination of high performance composite tubes containing high bulk modulus fluids. The new material system can potentially achieve a change in stiffness of several orders of magnitude through valve control. The F2MC material system is investigated in this research through analytical studies for active impedance control for load transfer reduction in transtibial prosthetic sockets and impedance joint control for ankle-foot orthoses (AFO). Preliminary analysis results indicate that the variable modulus system can reduce the load transfer between the limb and transtibial socket and can provide impedance tailoring for improving foot-slap in an AFO.

  1. Autonomous undulatory serpentine locomotion utilizing body dynamics of a fluidic soft robot.

    Science.gov (United States)

    Onal, Cagdas D; Rus, Daniela

    2013-06-01

    Soft robotics offers the unique promise of creating inherently safe and adaptive systems. These systems bring man-made machines closer to the natural capabilities of biological systems. An important requirement to enable self-contained soft mobile robots is an on-board power source. In this paper, we present an approach to create a bio-inspired soft robotic snake that can undulate in a similar way to its biological counterpart using pressure for actuation power, without human intervention. With this approach, we develop an autonomous soft snake robot with on-board actuation, power, computation and control capabilities. The robot consists of four bidirectional fluidic elastomer actuators in series to create a traveling curvature wave from head to tail along its body. Passive wheels between segments generate the necessary frictional anisotropy for forward locomotion. It takes 14 h to build the soft robotic snake, which can attain an average locomotion speed of 19 mm s(-1).

  2. Integratible Process for Fabrication of Fluidic Microduct Networks on a Single Wafer

    Energy Technology Data Exchange (ETDEWEB)

    Matzke, C.M.; Ashby, C.I.; Bridges, M.M.; Griego, L.; Wong, C.C.

    1999-09-07

    We present a microelectronics fabrication compatible process that comprises photolithography and a key room temperature SiON thin film plasma deposition to define and seal a fluidic microduct network. Our single wafer process is independent of thermo-mechanical material properties, particulate cleaning, global flatness, assembly alignment, and glue medium application, which are crucial for wafer fusion bonding or sealing techniques using a glue medium. From our preliminary experiments, we have identified a processing window to fabricate channels on silicon, glass and quartz substrates. Channels with a radius of curvature between 8 and 50 {micro}m, are uniform along channel lengths of several inches and repeatable across the wafer surfaces. To further develop this technology, we have begun characterizing the SiON film properties such as elastic modulus using nanoindentation, and chemical bonding compatibility with other microelectronic materials.

  3. Accelerating a hybrid continuum-atomistic fluidic model with on-the-fly machine learning

    CERN Document Server

    Stephenson, David; Lockerby, Duncan A

    2016-01-01

    We present a hybrid continuum-atomistic scheme which combines molecular dynamics (MD) simulations with on-the-fly machine learning techniques for the accurate and efficient prediction of multiscale fluidic systems. By using a Gaussian process as a surrogate model for the computationally expensive MD simulations, we use Bayesian inference to predict the system behaviour at the atomistic scale, purely by consideration of the macroscopic inputs and outputs. Whenever the uncertainty of this prediction is greater than a predetermined acceptable threshold, a new MD simulation is performed to continually augment the database, which is never required to be complete. This provides a substantial enhancement to the current generation of hybrid methods, which often require many similar atomistic simulations to be performed, discarding information after it is used once. We apply our hybrid scheme to nano-confined unsteady flow through a high-aspect-ratio converging-diverging channel, and make comparisons between the new s...

  4. New Drop Fluidics Enabled by Magnetic-Field-Mediated Elastocapillary Transduction.

    Science.gov (United States)

    Biswas, Saheli; Pomeau, Yves; Chaudhury, Manoj K

    2016-07-12

    This research introduces a new drop fluidics that uses a deformable and stretchable elastomeric film as the platform instead of the commonly used rigid supports. Such a soft film impregnated with magnetic particles can be modulated with an external electromagnetic field that produces a vast array of topographical landscapes with varying surface curvature, which, in conjunction with capillarity, can direct and control the motion of water droplets efficiently and accurately. When a thin layer of oil is present on this film that is deformed locally, a centrosymmetric wedge is formed. A water droplet placed on this oil-laden film becomes asymmetrically deformed, thus producing a gradient of Laplace pressure within the droplet and setting it in motion. A simple theory is presented that accounts for the droplet speed in terms of such geometric variables as the volume of the droplet and the thickness of the oil film covering the soft elastomeric film as well as material variables such as the viscosity of the oil and the interfacial tension of the oil-water interfaces. Following the verification of the theoretical result using well-controlled model systems, we demonstrate how the electromagnetically controlled elastocapillary force can be used to manipulate the motion of single and/or multiple droplets on the surface of the elastomeric film and how elementary operations such as drop fusion and thermally addressed chemical transformation can be carried out in aqueous droplets. It is expected that the resulting drop fluidics would be suitable for the digital control of drop motion by simply switching on and off the electromagnetic fields applied at different positions underneath the elastomeric film in a Boolean sequence. We anticipate that this method of directing and manipulating water droplets is poised for application in various biochemical reaction engineering situations, an example of which is the polymerase chain reaction (PCR).

  5. Design and implementation of fluidic micro-pulleys for flow control on centrifugal microfluidic platforms.

    Science.gov (United States)

    Soroori, Salar; Kulinsky, Lawrence; Kido, Horacio; Madou, Marc

    2014-06-01

    Microfluidic discs have been employed in a variety of applications for chemical analyses and biological diagnostics. These platforms offer a sophisticated fluidic toolbox, necessary to perform processes that involve sample preparation, purification, analysis, and detection. However, one of the weaknesses of such systems is the uni-directional movement of fluid from the disc center to its periphery due to the uni-directionality of the propelling centrifugal force. Here we demonstrate a mechanism for fluid movement from the periphery of a hydrophobic disc toward its center that does not rely on the energy supplied by any peripheral equipment. This method utilizes a ventless fluidic network that connects a column of working fluid to a sample fluid. As the working fluid is pushed by the centrifugal force to move toward the periphery of the disc, the sample fluid is pulled up toward the center of the disc analogous to a physical pulley where two weights are connected by a rope passed through a block. The ventless network is analogous to the rope in the pulley. As the working fluid descends, it creates a negative pressure that pulls the sample fluid up. The sample and working fluids do not come into direct contact and it allows the freedom to select a working fluid with physical properties markedly different from those of the sample. This article provides a demonstration of the "micro-pulley" on a disc, discusses underlying physical phenomena, provides design guidelines for fabrication of micro-pulleys on discs, and outlines a vision for future micro-pulley applications.

  6. Dielectric elastomer strain and pressure sensing enable reactive soft fluidic muscles

    Science.gov (United States)

    Veale, Allan J.; Anderson, Iain A.; Xie, Sheng Q.

    2016-04-01

    Wearable assistive devices are the future of rehabilitation therapy and bionic limb technologies. Traditional electric, hydraulic, and pneumatic actuators can provide the precise and powerful around-the-clock assistance that therapists cannot deliver. However, they do so in the confines of highly controlled factory environments, resulting in actuators too rigid, heavy, and immobile for wearable applications. In contrast, biological skeletal muscles have been designed and proven in the uncertainty of the real world. Bioinspired artificial muscle actuators aim to mimic the soft, slim, and self-sensing abilities of natural muscle that make them tough and intelligent. Fluidic artificial muscles are a promising wearable assistive actuation candidate, sharing the high-force, inherent compliance of their natural counterparts. Until now, they have not been able to self-sense their length, pressure, and force in an entirely soft and flexible system. Their use of rigid components has previously been a requirement for the generation of large forces, but reduces their reliability and compromises their ability to be comfortably worn. We present the unobtrusive integration of dielectric elastomer (DE) strain and pressure sensors into a soft Peano fluidic muscle, a planar alternative to the relatively bulky McKibben muscle. Characterization of these DE sensors shows they can measure the full operating range of the Peano muscle: strains of around 18% and pressures up to 400 kPa with changes in capacitance of 2.4 and 10.5 pF respectively. This is a step towards proprioceptive artificial muscles, paving the way for wearable actuation that can truly feel its environment.

  7. Alcid Nesting Habitat on the Maine Coast

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Maine supports an extensive seabird population because of the abundance of relatively inaccessible rocky coastal islands which are ideal nesting grounds for many...

  8. Adult Health: Worried About Empty Nest Syndrome?

    Science.gov (United States)

    ... clinical diagnosis. Instead, empty nest syndrome is a phenomenon in which parents experience feelings of sadness and loss when the last child leaves home. Although you might actively encourage your ...

  9. Annual survival of Florida nesting loggerheads

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 30 PAT tags were deployed on nesting loggerhead turtles at Juno Beach, FL in June 2012. There have been three premature pop-offs, one of which appeared to be a...

  10. Cackling Canada goose nesting populations, Yukon Delta

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Number of potential territories, number of cackling Canada Goose nests, and percent occupancy of available territories from CCG plots on the Yukon Delta National...

  11. Starling nest box monitoring [Rocky Mountain Arsenal

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document described the standard operating procedures for observing and recording data collected from starling nest box monitoring at the Rocky Mountain Arsenal....

  12. Chesapeake Bay Bald Eagle Nesting Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Chesapeake Bay population of breeding bald eagles increased dramatically in 1981 in not only the number of breeding pairs but in the number of nests hatching...

  13. Island's terns nest again after unsuccessful start

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — For five consecutive summers the Trustees of Reservations have directed a program on Nantucket for the protection of the terns which nest in several colonies around...

  14. Duck-nesting Studies: Lower Souris Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In this report an attempt has been made to summarize some of the notes made during the nesting studies at the Lower Souris Refuge in 1937. While assisting Mr....

  15. Nesting Loggerhead Sea Turtle Activity Report 2001

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper presents results from the 9th Annual Study (using Army Corp of Engineers funds) of nesting by the Atlantic loggerhead sea turtle (Caretta caretta) along...

  16. Nesting Loggerhead Sea Turtle Activity Report 1998

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper presents results from the sixth annual study of nesting along the Atlantic Oceanfront by the loggerhead sea turtle (Caretta carettd) in Virginia Beach,...

  17. Nesting Loggerhead Sea Turtle Activity Report 1999

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper presents results from the seventh annual study (using Army Corp of Engineers funds;) of nesting along the Atlantic Ocean coastline by the loggerhead sea...

  18. Linear Maps Preserving Idempotence on Nest Algebras

    Institute of Scientific and Technical Information of China (English)

    Jian Lian CUI; Jin Chuan HOU

    2004-01-01

    In this paper, we discuss the rank-1-preserving linear maps on nest algebras of Hilbertspace operators. We obtain several characterizations of such linear maps and apply them to show that a weakly continuous linear bijection on an atomic nest algebra is idempotent preserving if and only if it is a Jordan homomorphism, and in turn, if and only if it is an automorphism or an anti-automorphism.

  19. Gregarious nesting - An anti-predator response in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2012-01-01

    Gregarious nesting can be defined as a behaviour that occurs when a laying hen (Gallus gallus domesticus) given the choice between an occupied and an unoccupied nest site chooses the occupied nest site. It occurs frequently in flocks of laying hens kept under commercial conditions, contrasting...... the behaviour displayed by feral hens that isolate themselves from the flock during nesting activities. What motivates laying hens to perform gregarious nesting is unknown. One possibility is that gregarious nesting is an anti-predator response to the risk of nest predation emerging from behavioural flexibility...... in nesting strategy. The aim of the present experiment was to investigate whether gregarious nesting due to behavioural flexibility in nesting strategy is an anti-predator response. Twelve groups of 14–15 Isa Warren hens age 44 weeks were housed in pens each containing three adjacent roll-out nest boxes...

  20. Non-equilibrium molecular simulations of simple fluid transport at fluid-solid interfaces and fluidic behaviors at nanoscale

    Science.gov (United States)

    Yong, Xin

    Nano fluidics has shown promising potential for applications that could significantly impact our daily life, such as energy harvest, lab on a chip, desalination, etc. Current techniques to realize nano fluidic ideas are still very limited due to manufacturing technology. Although sub-micron fabrication techniques are undergoing rapid development recently, scientists and engineers are still not able to access actual nanometric systems. This reason prompts the development of computational tools to reveal physical principles underlying nano fluidic phenomena. Among various numerical approaches ranging from macroscopic to microscopic, molecular dynamics stands out because of its ability to faithfully model both equilibrium and non-equilibrium nanosystems by involving an appropriate amount of molecular details. The results from molecular dynamics simulations could elucidate essential physics and benefit designs of practical nano fluidic systems. This thesis attempts to provide the theoretical foundation for modeling nano fluidic systems, by investigating nanoscale fluid behaviors and nanoscale fluid-solid interfacial physics and transport for simple fluids via molecular dynamics simulations. Boundary-driven-shear, homogeneous-shear and reverse non-equilibrium molecular dynamics methods are implemented to generate non-equilibrium systems. The fundamental fluid behaviors such as velocity profile, temperature distribution and rheological material functions under steady planar shear are explored comprehensively by each method corresponding to different perspectives. The influences of nanoscale confinement are analyzed from the comparison among these methods. The advantages and disadvantages of each method are clarified, which provide guidance to conduct appropriate molecular dynamics simulations for nano fluidics. Further studies on the intrinsic slip of smooth solid surfaces is realized by the boundary-driven-shear method. Inspired by previous hypothesis of momentum

  1. Nest-site limitation and nesting resources of ants (Hymenoptera: Formicidae) in urban green spaces.

    Science.gov (United States)

    Friedrich, Russell; Philpott, Stacy M

    2009-06-01

    Urbanization impacts biodiversity, yet few studies examine general impacts of urbanization on insects. Furthermore, few studies examine availability and limitation of potential cavity nesting sites for ants, an important regulating factor in ant communities that may vary in different urban habitats. We compared three urban habitat types (gardens, vacant lots, and forests) in Toledo, OH, to examine availability and ant preferences for different cavity nesting resources (small and large hollow twigs and cavities). We added 72 artificial large hollow twigs (83 by 6 mm), small hollow twigs (140 by 2 mm), and spherical hollow cavities (6.52-31.1 cm(3) in volume, 1-mm opening) to six sites from May to August 2007 to determine whether nest-site limitation impacts ant communities. We collected natural nests to compare natural abundance and occupancy of cavity nests in different urban habitats. We opened artificial and natural nests to calculate the percentage occupied by cavity-nesting ants. Across all habitats, small twigs represented 81.1% of natural nests, spherical nests represented 10.1%, and large twigs 8.2%. Ants occupied 8.1% of natural large twigs, 14.6% of cavities, and 4.1% of small twigs. For artificial nests, 21.5% of large twigs, 1% of small twigs, and 1% of spheres were occupied. The high percentage of occupied artificial large twigs could imply this is a preferred and limiting resource in urban habitats. The results show that certain types of nesting resources may be an important factor mediating ant communities in urban green spaces.

  2. Nesting Activity of Loggerhead Turtles (Caretta caretta at Göksu Delta, Turkey during 2004 and 2008 nesting seasons

    Directory of Open Access Journals (Sweden)

    Salih H. Durmus

    2011-07-01

    Full Text Available Göksu Delta is one of the most important nesting beaches in Turkey for the endangered loggerhead turtle (Caretta caretta. This paper provides information on the nesting activities of loggerhead turtles, the spatial and temporal distribution of nesting, nesting success, nesting density, hatching success, incubation duration and clutch size over two nesting seasons. A total of 902 emergences occurred over two seasons, of which 239 (26.5% nests were deposited (137 nests in 2004 and 102 nests in 2008 and the overall mean nesting density was 3.4 nests/km. The peak of nesting emergences takes place mainly in June. Of the overall nests, 226 (94.6% were excavated and 16044 eggs were counted. Of these eggs, 3680 (22.9% hatchlings emerged and 2695 (73.2% of hatchlings of them were able to reach the sea. The mean number of eggs per clutch was 71 (range: 15 – 143. The shortest and longest incubation duration in these 2 seasons ranged from 46 to 62 days with a mean of 53 days. The main problems are negatively affecting loggerhead turtle population at Göksu Delta are dense jackal predation both adult and eggs and inundation in nests. The average nesting effort here (mean: 119.5 nests/season confirms that Göksu Delta is one of the most important nesting sites for loggerhead turtles in Turkey.

  3. The effects of large beach debris on nesting sea turtles

    Science.gov (United States)

    Fujisaki, Ikuko; Lamont, Margaret M.

    2016-01-01

    A field experiment was conducted to understand the effects of large beach debris on sea turtle nesting behavior as well as the effectiveness of large debris removal for habitat restoration. Large natural and anthropogenic debris were removed from one of three sections of a sea turtle nesting beach and distributions of nests and false crawls (non-nesting crawls) in pre- (2011–2012) and post- (2013–2014) removal years in the three sections were compared. The number of nests increased 200% and the number of false crawls increased 55% in the experimental section, whereas a corresponding increase in number of nests and false crawls was not observed in the other two sections where debris removal was not conducted. The proportion of nest and false crawl abundance in all three beach sections was significantly different between pre- and post-removal years. The nesting success, the percent of successful nests in total nesting attempts (number of nests + false crawls), also increased from 24% to 38%; however the magnitude of the increase was comparably small because both the number of nests and false crawls increased, and thus the proportion of the nesting success in the experimental beach in pre- and post-removal years was not significantly different. The substantial increase in sea turtle nesting activities after the removal of large debris indicates that large debris may have an adverse impact on sea turtle nesting behavior. Removal of large debris could be an effective restoration strategy to improve sea turtle nesting.

  4. 50 CFR 22.27 - Removal of eagle nests.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Removal of eagle nests. 22.27 Section 22... WILDLIFE AND PLANTS (CONTINUED) EAGLE PERMITS Eagle Permits § 22.27 Removal of eagle nests. (a) Purpose and... active or inactive nest where necessary to alleviate a safety emergency; (ii) An inactive eagle nest...

  5. Use of PLL-g-PEG in micro-fluidic devices for localizing selective and specific protein binding.

    Science.gov (United States)

    Marie, Rodolphe; Beech, Jason P; Vörös, Janos; Tegenfeldt, Jonas O; Höök, Fredrik

    2006-11-21

    By utilizing flow-controlled PLL-g-PEG and PLL-g-PEGbiotin modification of predefined regions of a poly(dimethylsiloxane) (PDMS) micro-fluidic device, with an intentionally chosen large (approximately 1 cm2) internal surface area, we report rapid (10 min), highly localized (6 x 10(-6) cm2), and specific surface-based protein capture from a sample volume (100 microL) containing a low amount of protein (160 attomol in pure buffer and 400 attomol in serum). The design criteria for this surface modification were achieved using QCM-D (quartz crystal microbalance with energy dissipation monitoring) of serum protein adsorption onto PLL-g-PEG-modified oxidized PDMS. Equally good, or almost as good, results were obtained for oxidized SU-8, Topas, and poly(methyl metacrylate) (PMMA), demonstrating the generic potential of PLL-g-PEG for surface modification in various micro-fluidic applications.

  6. Improved DNA extraction efficiency from low level cell numbers using a silica monolith based micro fluidic device.

    Science.gov (United States)

    Kashkary, Loay; Kemp, Cordula; Shaw, Kirsty J; Greenway, Gillian M; Haswell, Stephen J

    2012-10-31

    The evaluation of a micro fluidic system with an integrated silica monolith for performing DNA extraction from limited biological samples has been carried out. Low DNA target concentrations usually require the addition of carrier RNA to ensure desired extraction efficiencies. Here, we demonstrate a micro fluidic extraction system with increasingly efficient extraction performances for biological samples containing extracted DNA showed successful amplification via the polymerase chain reaction demonstrating both the effectiveness of the proposed system at removing potential inhibitors and yielding good quality DNA. The work presented here beneficially identifies reduced sample volumes/concentrations as suitable for processing with respect to downstream analysis by enabling pre-concentration of the biological sample, particularly important when dealing with clinical or forensic specimens.

  7. Nested Canalyzing, Unate Cascade, and Polynomial Functions.

    Science.gov (United States)

    Jarrah, Abdul Salam; Raposa, Blessilda; Laubenbacher, Reinhard

    2007-09-15

    This paper focuses on the study of certain classes of Boolean functions that have appeared in several different contexts. Nested canalyzing functions have been studied recently in the context of Boolean network models of gene regulatory networks. In the same context, polynomial functions over finite fields have been used to develop network inference methods for gene regulatory networks. Finally, unate cascade functions have been studied in the design of logic circuits and binary decision diagrams. This paper shows that the class of nested canalyzing functions is equal to that of unate cascade functions. Furthermore, it provides a description of nested canalyzing functions as a certain type of Boolean polynomial function. Using the polynomial framework one can show that the class of nested canalyzing functions, or, equivalently, the class of unate cascade functions, forms an algebraic variety which makes their analysis amenable to the use of techniques from algebraic geometry and computational algebra. As a corollary of the functional equivalence derived here, a formula in the literature for the number of unate cascade functions provides such a formula for the number of nested canalyzing functions.

  8. Nest survival patterns in Eurasian Bittern: effect of nest age, time and habitat variables

    Directory of Open Access Journals (Sweden)

    Marcin Polak

    2016-06-01

    Full Text Available Determining the key factors affecting the reproductive success of nesting birds is crucial in order to better understand the population dynamics of endangered species and to introduce effective conservation programmes for them. Inhabiting a variety of wetland habitats, aquatic birds actively select safe nesting sites so as to protect their nests against predators. The main aim of the present work was to assess the effect of temporal and habitat variables on the daily nest survival rate of Eurasian Bitterns colonizing semi–natural fishpond habitat in eastern Poland. MARK software was used for the modelling. Eurasian Bittern nests were most vulnerable to depredation at the beginning of the breeding season. This was probably because the reedbed vegetation at this time was not yet dense enough to effectively conceal the nests. There was a positive relationship between nest age and the daily survival rate. Two of the habitat variables analysed were of the greatest significance: water depth and vegetation density. In the Eurasian Bittern population studied here, nests built over deep water and in dense vegetation had the best chances of survival. The results of this work may be useful in the preparation of plans for the conservation and management of populations of this rare and endangered species. Conservation and restoration efforts that attempt to maintain high water levels will be especially beneficial to this avian species that is dependent on wetland ecosystems for breeding.

  9. The influence of regional hydrology on nesting behavior and nest fate of the American alligator

    Science.gov (United States)

    Ugarte, Cristina A.; Bass, Oron L.; Nuttle, William; Mazzotti, Frank J.; Rice, Kenneth G.; Fujisaki, Ikuko; Whelan, Kevin R.T.

    2013-01-01

    Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species.

  10. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM)

    OpenAIRE

    Ladeesh V. G.; Manu R

    2017-01-01

    Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of mac...

  11. Behavior of Puerto Rican parrots during failed nesting attempts

    Science.gov (United States)

    Wilson, K.A.; Wilson, M.H.; Field, R.

    1997-01-01

    We compared patterns of nesting behavior of four pairs of Puerto Rican Parrots (Amazona vittata) that experienced failed nesting attempts to behavior of four pairs of parrots that experienced no substantial nest problems and successfully fledged young without management intervention. Only changes in female parrots' behavior were clearly associated with nest failure. During incubation, decreases in nest attendance, increases in duration of recesses, and increases in frequency of nest entries by female parrots were associated with imminent abandonment of nests. During early chick rearing, similar behavior was associated with the loss of broods. Low nest attendance and long recesses by female parrots during incubation were also associated with successful hatching of eggs followed by death of young several days later. The behavior patterns and changes in Puerto Rican Parrot nesting behavior described in this paper may alert biologists to nest problems that might be mitigated by management intervention.

  12. Robust and Optimal Control of Magnetic Microparticles inside Fluidic Channels with Time-Varying Flow Rates

    Directory of Open Access Journals (Sweden)

    Islam S.M. Khalil

    2016-06-01

    Full Text Available Targeted therapy using magnetic microparticles and nanoparticles has the potential to mitigate the negative side-effects associated with conventional medical treatment. Major technological challenges still need to be addressed in order to translate these particles into in vivo applications. For example, magnetic particles need to be navigated controllably in vessels against flowing streams of body fluid. This paper describes the motion control of paramagnetic microparticles in the flowing streams of fluidic channels with time-varying flow rates (maximum flow is 35 ml.hr−1. This control is designed using a magnetic-based proportional-derivative (PD control system to compensate for the time-varying flow inside the channels (with width and depth of 2 mm and 1.5 mm, respectively. First, we achieve point-to-point motion control against and along flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1. The average speeds of single microparticle (with average diameter of 100 μm against flow rates of 6 ml.hr−1 and 30 ml.hr−1 are calculated to be 45 μm.s−1 and 15 μm.s−1, respectively. Second, we implement PD control with disturbance estimation and compensation. This control decreases the steady-state error by 50%, 70%, 73%, and 78% at flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1, respectively. Finally, we consider the problem of finding the optimal path (minimal kinetic energy between two points using calculus of variation, against the mentioned flow rates. Not only do we find that an optimal path between two collinear points with the direction of maximum flow (middle of the fluidic channel decreases the rise time of the microparticles, but we also decrease the input current that is supplied to the electromagnetic coils by minimizing the kinetic energy of the microparticles, compared to a PD control with disturbance compensation.

  13. Robust and Optimal Control of Magnetic Microparticles Inside Fluidic Channels with Time-varying Flow Rates

    Directory of Open Access Journals (Sweden)

    Islam S.M. Khalil

    2016-06-01

    Full Text Available Targeted therapy using magnetic microparticles and nanoparticles has the potential to mitigate the negative side-effects associated with conventional medical treatment. Major technological challenges still need to be addressed in order to translate these particles into in vivo applications. For example, magnetic particles need to be navigated controllably in vessels against flowing streams of body fluid. This paper describes the motion control of paramagnetic microparticles in the flowing streams of fluidic channels with time-varying flow rates (maximum flow is 35 ml.hr-1. This control is designed using a magnetic-based proportional-derivative (PD control system to compensate for the time-varying flow inside the channels (with width and depth of 2 mm and 1.5 mm, respectively. First, we achieve point-to-point motion control against and along flow rates of 4 ml.hr-1, 6 ml.hr-1, 17 ml.hr-1, and 35 ml.hr-1. The average speeds of single microparticle (with average diameter of 100 μm against flow rates of 6 ml.hr-1 and 30 ml.hr-1 are calculated to be 45 μm.s-1 and 15 μm.s-1, respectively. Second, we implement PD control with disturbance estimation and compensation. This control decreases the steady-state error by 50%, 70%, 73%, and 78% at flow rates of 4 ml.hr-1, 6 ml.hr-1, 17 ml.hr-1, and 35 ml.hr-1, respectively. Finally, we consider the problem of finding the optimal path (minimal kinetic energy between two points using calculus of variation, against the mentioned flow rates. Not only do we find that an optimal path between two collinear points with the direction of maximum flow (middle of the fluidic channel decreases the rise time of the microparticles, but we also decrease the input current that is supplied to the electromagnetic coils by minimizing the kinetic energy of the microparticles, compared to a PD control with disturbance compensation.

  14. Simulation of the fluidic features for diffuser/nozzle involved in a PZT-based valveless micropump

    Institute of Scientific and Technical Information of China (English)

    HouWensheng; Zheng Xiaolin; Biswajit Das; Jiang Yingtao; Qian Shizhi; Wu Xiaoying; Zheng Zhigao

    2008-01-01

    PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids, and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing along a specific direction. In this paper, a numerical model of micropump has been proposed, and the fluidic properties of diffuser/nozzle have been simulated with ANSYS. With the method of finite-element analysis, the increased pressure drop between inlet and outlet of diffuser/nozzle induces the increment of flow rate in both diffuser and nozzle simultaneously, but the increasing rate of diffuser is faster than that of nozzle. The L/R, ratio of L (length of cone pipe) and R (radius of minimal cross section of cone pipe) plays an important role in fluidic performance of diffuser and nozzle as well, and the mean flow rate will decrease with increment of L/R. The mean flow rate reaches its peak value when L/R with the value of 10 regardless the divergence angle of diffuser or nozzle. The simulation results indicate that the fluidic properties of diffuser/nozzle can be defined by its geometric structure, and accordingly determine the efficiency of micropump.

  15. A simple method for the evaluation of microfluidic architecture using flow quantitation via a multiplexed fluidic resistance measurement.

    Science.gov (United States)

    Leslie, Daniel C; Melnikoff, Brett A; Marchiarullo, Daniel J; Cash, Devin R; Ferrance, Jerome P; Landers, James P

    2010-08-07

    Quality control of microdevices adds significant costs, in time and money, to any fabrication process. A simple, rapid quantitative method for the post-fabrication characterization of microchannel architecture using the measurement of flow with volumes relevant to microfluidics is presented. By measuring the mass of a dye solution passed through the device, it circumvents traditional gravimetric and interface-tracking methods that suffer from variable evaporation rates and the increased error associated with smaller volumes. The multiplexed fluidic resistance (MFR) measurement method measures flow via stable visible-wavelength dyes, a standard spectrophotometer and common laboratory glassware. Individual dyes are used as molecular markers of flow for individual channels, and in channel architectures where multiple channels terminate at a common reservoir, spectral deconvolution reveals the individual flow contributions. On-chip, this method was found to maintain accurate flow measurement at lower flow rates than the gravimetric approach. Multiple dyes are shown to allow for independent measurement of multiple flows on the same device simultaneously. We demonstrate that this technique is applicable for measuring the fluidic resistance, which is dependent on channel dimensions, in four fluidically connected channels simultaneously, ultimately determining that one chip was partially collapsed and, therefore, unusable for its intended purpose. This method is thus shown to be widely useful in troubleshooting microfluidic flow characteristics.

  16. Buteo Nesting Ecology: Evaluating Nesting of Swainson’s Hawks in the Northern Great Plains

    Science.gov (United States)

    Inselman, Will M.; Datta, Shubham; Jenks, Jonathan A.; Jensen, Kent C.; Grovenburg, Troy W.

    2015-01-01

    Swainson’s hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson’s hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson’s hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, SDist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%–42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson’s hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson’s hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson’s hawks arriving to the breeding grounds. PMID:26327440

  17. Nest-site selection, nesting behaviour and spatial ecology of female Nile crocodiles (Crocodylus niloticus) in South Africa.

    Science.gov (United States)

    Combrink, Xander; Warner, Jonathan K; Downs, Colleen T

    2017-02-01

    Nesting biology and ecology have been investigated for Nile crocodiles (Crocodylus niloticus), but information on behaviour and movement patterns of nesting females during nest guarding is scant. Consequently, we investigated the home ranges, nest-site selection strategies, movement patterns, activity levels and nest fidelity of four nesting females using telemetry. Gravid females selected winter basking/breeding areas close (351±2m) to nest-sites. Mean home range and core-use areas of nesting females were 8539±4752m(2), and 4949±3302m(2) respectively. Mean home range (0.85ha) was significantly smaller than those of non-nesting females (108.4ha) during nesting season. Activity levels and mean daily movements while nesting were 8.1±2.5% and 213±64m, respectively, and increased to 47.9±11.7% and 2176±708m post-nesting. Overall levels of nest fidelity were 82.8±11.7%, (day 78.1±15.9%; night 87.3±7.8%). Highest nest fidelity recorded during incubation was 99.7% over 96days. Telemetry data from nesting females were helpful for elucidating spatial and behavioural patterns during the nest guarding period, and provided novel insights into this biologically important event.

  18. Boolean nested canalizing functions: a comprehensive analysis

    CERN Document Server

    Li, Yuan; Murrugarra, David; Aguilar, Boris; Laubenbacher, Reinhard

    2012-01-01

    Boolean network models of molecular regulatory networks have been used successfully in computational systems biology. The Boolean functions that appear in published models tend to have special properties, in particular the property of being nested canalizing, a property inspired by the concept of canalization in evolutionary biology. It has been shown that networks comprised of nested canalizing functions have dynamic properties that make them suitable for modeling molecular regulatory networks, namely a small number of (large) attractors, as well as relatively short limit cycles. This paper contains a detailed analysis of this class of functions, based on a novel normal form as polynomial functions over the Boolean field. The concept of layer is introduced that stratifies variables into different classes depending on their level of dominance. Using this layer concept a closed form formula is derived for the number of nested canalizing functions with a given number of variables. Additional metrics analyzed in...

  19. Ashtabula Breakwater Common Tern (Sterna Hirundo) Nesting

    Science.gov (United States)

    2016-05-01

    purchased from GG Telecom, Victoriaville, QC, Canada and connected to the solar panel system to help document activities at the site. Volunteers...blocks. Large 8’ x 8’ x 4’ blocks were used to form the base or toe of the structure, and smaller angled blocks were used to create the side slope...to nest. In addition to placing the blocks on top of the wall, lengths of angle iron were bolted down to attach the nesting blocks to those below

  20. PolyChord: nested sampling for cosmology

    CERN Document Server

    Handley, W J; Lasenby, A N

    2015-01-01

    PolyChord is a novel nested sampling algorithm tailored for high dimensional parameter spaces. In addition, it can fully exploit a hierarchy of parameter speeds such as is found in CosmoMC and CAMB. It utilises slice sampling at each iteration to sample within the hard likelihood constraint of nested sampling. It can identify and evolve separate modes of a posterior semi-independently and is parallelised using openMPI. PolyChord is available for download at: http://ccpforge.cse.rl.ac.uk/gf/project/polychord/

  1. A New Drop Fluidics Enabled by Magnetic Field Mediated Elasto-Capillary Transduction

    CERN Document Server

    Biswas, Saheli; Chaudhury, Manoj K

    2016-01-01

    This research introduces a new drop fluidics, which uses a deformable and stretchable elastomeric film as the platform, instead of the commonly used rigid supports. Such a soft film impregnated with magnetic particles can be modulated with an external electromagnetic field that produces a vast array of topographical landscapes with varying surface curvature, which, in conjunction with capillarity, can direct and control motion of water droplets efficiently and accurately. When a thin layer of oil is present on this film that is deformed locally, a centrosymmetric wedge is formed. A water droplet placed on this oil laden film becomes asymmetrically deformed thus producing a gradient of Laplace pressure within the droplet setting it to motion. A simple theory is presented that accounts for the droplet speed in terms of such geometric variables as the volume of the droplet and the thickness of the oil film covering the soft elastomeric film, as well as such material variables as the viscosity of the oil and inte...

  2. The use of micro-/milli-fluidics to better understand the mechanisms behind deep venous thrombosis

    Science.gov (United States)

    Schofield, Zoe; Alexiadis, Alessio; Brill, Alexander; Nash, Gerard; Vigolo, Daniele

    2016-11-01

    Deep venous thrombosis (DVT) is a dangerous and painful condition in which blood clots form in deep veins (e.g., femoral vein). If these clots become unstable and detach from the thrombus they can be delivered to the lungs resulting in a life threatening complication called pulmonary embolism (PE). Mechanisms of clot development in veins remain unclear but researchers suspect that the specific flow patterns in veins, especially around the valve flaps, play a fundamental role. Here we show how it is now possible to mimic the current murine model by developing micro-/milli-fluidic experiments. We exploited a novel detection technique, ghost particle velocimetry (GPV), to analyse the velocity profiles for various geometries. These vary from regular microfluidics with a rectangular cross section with a range of geometries (mimicking the presence of side and back branches in veins, closed side branch and flexible valves) to a more accurate venous representation with a 3D cylindrical geometry obtained by 3D printing. In addition to the GPV experiments, we analysed the flow field developing in these geometries by using computational fluid dynamic simulations to develop a better understanding of the mechanisms behind DVT. ZS gratefully acknowledges financial support from the EPSRC through a studentship from the Sci-Phy-4-Health Centre for Doctoral Training (EP/L016346/1).

  3. The time-resolved natural flow field of a fluidic oscillator

    Science.gov (United States)

    Woszidlo, Rene; Ostermann, Florian; Nayeri, C. N.; Paschereit, C. O.

    2015-06-01

    The internal and external flow field of a fluidic oscillator with two feedback channels are examined experimentally within the incompressible flow regime. A scaled-up device with a square outlet nozzle is supplied with pressurized air and emits a spatially oscillating jet into quiescent environment. Time-resolved information are obtained by phase-averaging pressure and PIV data based on an internal reference signal. The temporal resolution is better than a phase angle of 3°. A detailed analysis of the internal dynamics reveals that the oscillation mechanism is based on fluid feeding into a separation bubble between the jet and mixing chamber wall which pushes the jet to the opposite side. The total volume of fluid transported through one feedback channel during one oscillation cycle matches the total growth of the separation bubble from its initial size to its maximum extent. Although the oscillation frequency increases linearly with supply rate, sudden changes in the internal dynamics are observed. These changes are caused by a growth in reversed flow through the feedback channels. The time-resolved properties of the emitted jet such as instantaneous jet width and exit velocity are found to oscillate substantially during one oscillation cycle. Furthermore, the results infer that the jet's oscillation pattern is approximately sinusoidal with comparable residence and switching times.

  4. Bioengineering bacteriophages to enhance the sensitivity of phage amplification-based paper fluidic detection of bacteria.

    Science.gov (United States)

    Alcaine, S D; Law, K; Ho, S; Kinchla, A J; Sela, D A; Nugen, S R

    2016-08-15

    Bacteriophage (phage) amplification is an attractive method for the detection of bacteria due to a narrow phage-host specificity, short amplification times, and the phages' ability to differentiate between viable and non-viable bacterial cells. The next step in phage-based bacteria detection is leveraging bioengineered phages to create low-cost, rapid, and easy-to-use detection platforms such as lateral flow assays. Our work establishes the proof-of-concept for the use of bioengineered T7 phage strains to increase the sensitivity of phage amplification-based lateral flow assays. We have demonstrated a greater than 10-fold increase in sensitivity using a phage-based protein reporter, maltose-binding protein, over the detection of replicated T7 phage viron itself, and a greater then 100-fold increase in sensitivity using a phage-based enzymatic reporter, alkaline phosphatase. This increase in sensitivity enabled us to detect 10(3)CFU/mL of Escherichia coli in broth after 7h, and by adding a filter concentration step, the ability to detect a regulatory relevant E. coli concentration of 100CFU/100mL in inoculated river water after 9h, where the current standard requires days for results. The combination of the paper fluidic format with phage-based detection provides a platform for the development of novel diagnostics that are sensitive, rapid, and easy to use.

  5. A universal label-free biosensing platform based on opto-fluidic ring resonators

    Science.gov (United States)

    Zhu, Hongying; White, Ian M.; Suter, Jonathan D.; Gohring, John; Fan, Xudong

    2009-02-01

    Rapid and accurate detection of biomolecules is important for medical diagnosis, pharmaceuticals, homeland security, food quality control, and environmental protection. A simple, low cost and highly sensitive label-free optical biosensor based on opto-fluidic ring resonator (OFRR) has been developed that naturally integrates microfluidics with ring resonators. The OFRR employs a piece of fused silica capillary with a diameter around 100 micrometers. The circular cross section of the capillary forms the ring resonator and light repeatedly travels along the resonator circumference in the form of whispering gallery modes (WGMs) through total internal reflection. When the capillary wall is as thin as a couple of micrometers (detect the target molecules with high specificity, the OFRR inner surface is functionalized with receptors, such as antibodies, peptide-displayed bacteriophage or oligonucleotide DNA probes. The WGM spectral position shifts when biomolecules bind to the OFRR inner surface and change the local refractive index, which provides quantitative and kinetic information about the biomolecule interaction near the OFRR inner surface. The OFRR has been successfully demonstrated for detection of various types of biomoelcuels. Here, we will first introduce the basic operation principle of the OFRR as a sensor and then application examples of the OFRR in the detection of proteins, disease biomarkers, virus, DNA molecules, and cells with high sensitivities will be presented.

  6. Dual-wavelength optical fluidic glucose sensor using time series analysis of d(+)-glucose measurement

    Science.gov (United States)

    Tang, Jing-Yau; Chen, Nan-Yueh; Chen, Ming-Kun; Wang, Min-Haw; Jang, Ling-Sheng

    2016-10-01

    This paper presents a rising-edge time-series analysis (TSA) method that can be applied to a dual-wavelength optical fluidic glucose sensor (DWOFGS). In the experiment, the concentration of glucose in phosphate buffered saline (PBS) was determined by measuring the absorbance of the solution as determined by variation in the rising edge of the photodiode (PD) voltage response waveform. The DWOFGS principle is based on near-infrared (NIR) absorption spectroscopy at selected dual wavelengths (1450 and 1650 nm) in the first overtone band. The DWOFGS comprises two light-emitting diodes (LEDs) and two PD detectors. No additional fibers or lenses are required in our device. The output light level of the LEDs is adjusted to a light intensity suitable to the glucose absorption rate in an electronic circuit. Four light absorbance paths enable detection of d(+)-glucose concentrations from 0 to 20 wt % in steps of 5 wt %. The glucose light absorbance process was calculated based on the rising edge of the PD waveform under a low-intensity light source using TSA. The TSA method can be used to obtain the glucose level in PBS and reduce measurement background noise. The application of the rising-edge TSA method improves sensor sensitivity, increases the accuracy of the data analysis, and lowers measurement equipment costs.

  7. Improved micromachined column design and fluidic interconnects for programmed high-temperature gas chromatography separations.

    Science.gov (United States)

    Gaddes, David; Westland, Jessica; Dorman, Frank L; Tadigadapa, Srinivas

    2014-07-01

    This work focuses on the development and experimental evaluation of micromachined chromatographic columns for use in a commercial gas chromatography (GC) system. A vespel/graphite ferrule based compression sealing technique is presented using which leak-proof fluidic interconnection between the inlet tubing and the microchannel was achieved. This sealing technique enabled separation at temperatures up to 350°C on a μGC column. This paper reports the first high-temperature separations in microfabricated chromatographic columns at these temperatures. A 2m microfabricated column using a double Archimedean spiral design with a square cross-section of 100μm×100μm has been developed using silicon microfabrication techniques. The microfabricated column was benchmarked against a 2m 100μm diameter commercial column and the performance between the two columns was evaluated in tests performed under identical conditions. High temperature separations of simulated distillation (ASTM2887) and polycyclic aromatic hydrocarbons (EPA8310) were performed using the μGC column in temperature programmed mode. The demonstrated μGC column along with the high temperature fixture offers one more solution toward potentially realizing a portable μGC device for the detection of semi-volatile environmental pollutants and explosives without the thermal limitations reported to date with μGC columns using epoxy based interconnect technology.

  8. An angular fluidic channel for prism-free surface-plasmon-assisted fluorescence capturing

    Science.gov (United States)

    Nomura, Ken-Ichi; Gopinath, Subash C. B.; Lakshmipriya, Thangavel; Fukuda, Nobuko; Wang, Xiaomin; Fujimaki, Makoto

    2013-12-01

    Surface plasmon excitation provides stronger enhancement of the fluorescence intensity and better sensitivity than other sensing approaches but requires optimal positioning of a prism to ensure optimum output of the incident light. Here we describe a simple, highly sensitive optical sensing system combining surface plasmon excitation and fluorescence to address this limitation. V-shaped fluidic channels are employed to mimic the functions of a prism, sensing plate, and flow channel in a single setup. Superior performance is demonstrated for different biomolecular recognition reactions on a self-assembled monolayer, and the sensitivity reaches 100 fM for biotin-streptavidin interactions. Using an antibody as a probe, we demonstrate the detection of intact influenza viruses at 0.2 HA units ml-1 levels. The convenient sensing system developed here has the advantages of being prism-free and requiring less sample (1-2 μl), making this platform suitable for use in situations requiring low sample volumes.

  9. Optimization of elstomeric micro-fluidic valve dimensions using non-linear finite element methods

    Directory of Open Access Journals (Sweden)

    H Khawaja

    2016-04-01

    Full Text Available We use a nonlinear finite element (FE method model to compare,optimize and determine the limits for useful geometries of microfluidicvalves in elastomer polydimethylsiloxane (PDMS. Simulations havebeen performed with the aim of finding the optimal shape, size andlocation of pressurization that minimizes the pressure required to operatethe valve. One important constraint governing the design parameters isthat the stresses should be within elastic limits, so that the componentremains safe from any type of structural failure. To obtain reliable results,non-linear stress analysis was performed using the Mooney-Rivlin 9parameter approximation which is based on the Hyper Elastic MaterialModel. A 20 noded brick element was used for the development of FEmodel. Mesh sensitivity analysis was also performed to assess the qualityof the results. The simulations were performed with commerciallyavailable FE modeling software, developed by ANSYS Inc. to determinethe effect of varying different geometric parameters on the performanceof micro-fluidic valves.The aim of this work is to determine the geometry of the channel crosssectionthat would result in the largest deflection for the least appliedpressure, i.e. to minimize the pressure needed to operate the valve.

  10. Zone fluidics for measurement of octanol-water partition coefficient of drugs.

    Science.gov (United States)

    Wattanasin, Panwadee; Saetear, Phoonthawee; Wilairat, Prapin; Nacapricha, Duangjai; Teerasong, Saowapak

    2015-02-20

    A novel zone fluidics (ZF) system for the determination of the octanol-water partition coefficient (Pow) of drugs was developed. The ZF system consisted of a syringe pump with a selection valve, a holding column, a silica capillary flow-cell and an in-line spectrophotometer. Exact microliter volumes of solvents (octanol and phosphate buffer saline) and a solution of the drug, sandwiched between air segments, were sequentially loaded into the vertically aligned holding column. Distribution of the drug between the aqueous and octanol phases occurred by the oscillation movement of the syringe pump piston. Phase separation occurred due to the difference in densities. The liquid zones were then pushed into the detection flow cell. In this method, absorbance measurements in only one of the phase (octanol or aqueous) were employed, which together with the volumes of the solvents and pure drug sample, allowed the calculation of the Pow. The developed system was applied to the determination of the Pow of some common drugs. The log (Pow) values agreed well with a batch method (R(2)=0.999) and literature (R(2)=0.997). Standard deviations for intra- and inter-day analyses were both less than 0.1log unit. This ZF system provides a robust and automated method for screening of Pow values in the drug discovery process.

  11. Engineering fluidic delays in paper-based devices using laser direct-writing.

    Science.gov (United States)

    He, P J W; Katis, I N; Eason, R W; Sones, C L

    2015-10-21

    We report the use of a new laser-based direct-write technique that allows programmable and timed fluid delivery in channels within a paper substrate which enables implementation of multi-step analytical assays. The technique is based on laser-induced photo-polymerisation, and through adjustment of the laser writing parameters such as the laser power and scan speed we can control the depth and/or the porosity of hydrophobic barriers which, when fabricated in the fluid path, produce controllable fluid delay. We have patterned these flow delaying barriers at pre-defined locations in the fluidic channels using either a continuous wave laser at 405 nm, or a pulsed laser operating at 266 nm. Using this delay patterning protocol we generated flow delays spanning from a few minutes to over half an hour. Since the channels and flow delay barriers can be written via a common laser-writing process, this is a distinct improvement over other methods that require specialist operating environments, or custom-designed equipment. This technique can therefore be used for rapid fabrication of paper-based microfluidic devices that can perform single or multistep analytical assays.

  12. Investigation of injection molding of orthogonal fluidic connector for microfluidic devices

    Directory of Open Access Journals (Sweden)

    Zheng Xu

    2017-02-01

    Full Text Available Orthogonal fluidic connections are essential for developing multilayered microfluidic devices. At present, most orthogonal connectors are realized by a horizontal channel and a vertical channel in different plates. Therefore, some extra alignment and adhesion processes for precise plate assembly are required. In this paper, the method of injection molding is proposed to make a one-body-type orthogonal connector in a single plastic plate. The connector was composed of a cantilevered tube and the other in the substrate. An injection mold was developed in which a side core-pulling mechanism and an ejection mechanism of push-pipes were combined to form the mold for an orthogonal connector. Both the type and the location of gate were optimized for the mold. The results showed that the fan gate in the middle position of the plate was the most suitable in term of both defect control and practicability. The effect of melt temperature was numerically investigated and then verified experimentally. With the optimized parameters, the relative length and the relative wall thickness of a cantilevered tube in the plastic part can reach 98.89% and 99.80%, respectively. Furthermore, using the plastic part as a cover plate, a three-layer plastic microfluidic device was conveniently fabricated for electrochemical detection.

  13. Flexible fluidic microchips based on thermoformed and locally modified thin polymer films.

    Science.gov (United States)

    Truckenmüller, R; Giselbrecht, S; van Blitterswijk, C; Dambrowsky, N; Gottwald, E; Mappes, T; Rolletschek, A; Saile, V; Trautmann, C; Weibezahn, K-F; Welle, A

    2008-09-01

    This paper presents a fundamentally new approach for the manufacturing and the possible applications of lab on a chip devices, mainly in the form of disposable fluidic microchips for life sciences applications. The new technology approach is based on a novel microscale thermoforming of thin polymer films as core process. The flexibility not only of the semi-finished but partly also of the finished products in the form of film chips could enable future reel to reel processes in production but also in application. The central so-called 'microthermoforming' process can be surrounded by pairs of associated pre- and postprocesses for micro- and nanopatterned surface and bulk modification or functionalisation of the formed films. This new approach of microscale thermoforming of thin polymer film substrates overlaid with a split local modification of the films is called 'SMART', which stands for 'substrate modification and replication by thermoforming'. In the process, still on the unformed, plane film, the material modifications of the preprocess define the locations where later, then on the spatially formed film, the postprocess generates the final local modifications. So, one can obtain highly resolved modification patterns also on hardly accessible side walls and even behind undercuts. As a first application of the new technology, we present a flexible chip-sized scaffold for three dimensional cell cultivation in the form of a microcontainer array. The spatially warped container walls have been provided with micropores, cell adhesion micropatterns and thin film microelectrodes.

  14. Psychicones: Visual Traces of the Soul in Late Nineteenth-Century Fluidic Photography.

    Science.gov (United States)

    Pethes, Nicolas

    2016-07-01

    The article discusses attempts to visualise the soul on photographic plates at the end of the nineteenth century, as conducted by the French physician Hippolyte Baraduc in Paris. Although Baraduc refers to earlier experiments on fluidic photography in his book on The Human Soul (1896) and is usually mentioned as a precursor to parapsychological thought photography of the twentieth century, his work is presented as a genuine attempt at photographic soul-catching. Rather than producing mimetic representations of thoughts and imaginations, Baraduc claims to present the vital radiation of the psyche itself and therefore calls the images he produces psychicones. The article first discusses the difference between this method of soul photography and other kinds of occult media technologies of the time, emphasising the significance of its non-mimetic, abstract character: since the soul itself was considered an abstract entity, abstract traces seemed all the more convincing to the contemporary audience. Secondly, the article shows how the technological agency of photography allowed Baraduc's psychicones to be tied into related discourses in medicine and psychology. Insofar as the photographic plates displayed actual visual traces, Baraduc and his followers no longer considered hallucinations illusionary and pathological but emphasised the physical reality and normality of imagination. Yet, the greatest influence of soul photography was not on science but on art. As the third part of the paper argues, the abstract shapes on Baraduc's plates provided inspiration for contemporary avant-garde aesthetics, for example, Kandinsky's abstract paintings and the random streams of consciousness in surrealistic literature.

  15. Bio-inspired online variable recruitment control of fluidic artificial muscles

    Science.gov (United States)

    Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

    2016-12-01

    This paper details the creation of a hybrid variable recruitment control scheme for fluidic artificial muscle (FAM) actuators with an emphasis on maximizing system efficiency and switching control performance. Variable recruitment is the process of altering a system’s active number of actuators, allowing operation in distinct force regimes. Previously, FAM variable recruitment was only quantified with offline, manual valve switching; this study addresses the creation and characterization of novel, on-line FAM switching control algorithms. The bio-inspired algorithms are implemented in conjunction with a PID and model-based controller, and applied to a simulated plant model. Variable recruitment transition effects and chatter rejection are explored via a sensitivity analysis, allowing a system designer to weigh tradeoffs in actuator modeling, algorithm choice, and necessary hardware. Variable recruitment is further developed through simulation of a robotic arm tracking a variety of spline position inputs, requiring several levels of actuator recruitment. Switching controller performance is quantified and compared with baseline systems lacking variable recruitment. The work extends current variable recruitment knowledge by creating novel online variable recruitment control schemes, and exploring how online actuator recruitment affects system efficiency and control performance. Key topics associated with implementing a variable recruitment scheme, including the effects of modeling inaccuracies, hardware considerations, and switching transition concerns are also addressed.

  16. Nanobiomimetic Active Shape Control - Fluidic and Swarm-Intelligence Embodiments for Planetary Exploration

    Science.gov (United States)

    Santoli, S.

    The concepts of Active Shape Control ( ASC ) and of Generalized Quantum Holography ( GQH ), respectively embodying a closer approach to biomimicry than the current macrophysics-based attempts at bioinspired robotic systems, and realizing a non-connectionistic, life-like kind of information processing that allows increasingly depths of mimicking of the biological structure-function solidarity, which have been formulated in physical terms in previous papers, are here further investigated for application to bioinspired flying or swimming robots for planetary exploration. It is shown that nano-to-micro integration would give the deepest level of biomimicry, and that both low and very low Reynolds number ( Re ) fluidics would involve GQH and Fiber Bundle Topology ( FBT ) for processing information at the various levels of ASC bioinspired robotics. While very low Re flows lend themselves to geometrization of microrobot dynamics and to FBT design, the general design problem is geometrized through GQH , i.e. made independent of dynamic considerations, thus allowing possible problems of semantic dyscrasias in highly complex hierarchical dynamical chains of sensing information processing actuating to be overcome. A roadmap to near- and medium-term nanostructured and nano-to-micro integration realizations is suggested.

  17. Compound-fluidic electrospray:An efficient method for the fabrication of microcapsules with multicompartment structure

    Institute of Scientific and Technical Information of China (English)

    CHEN HongYan; ZHAO Yong; JIANG Lei

    2009-01-01

    Microcapsules with multiple compartments are of significant importance in many applications such as smart drug delivery,microreactor,complicated sensor,end so on. Here we report a novel compound-fluidic electrospray method that could fabricate multicompartment microcapsules in a single step. The as-prepared microcapsules have multiple compartments inside. The compartments are separated from each other by inner walls made from shell materials,and different content can be independently loaded in each of them without any contact. We assemble a hierarchical compound nozzle by inserting certain numbers of metallic inner capillaries separately into a blunt metal needle. The particular configuration of the compound nozzle induces a completely and independently envelope of core fluids by shell fluid,as a result of which mulicomponent microcapsules with multicompartment structure can be obtained. And also,the number of inner compartments and the corresponding encapsulated components can be controlled by rationally designing the configuration of the compound nozzle.This general method can be readily extended to many other functional materials,especially for the effective encapsulation of active ingredients,such as sensitive and reactive materials.

  18. Evaluation of fluidic thrust vectoring nozzle via thrust pitching angle and thrust pitching moment

    Science.gov (United States)

    Li, L.; Hirota, M.; Ouchi, K.; Saito, T.

    2016-03-01

    Shock vector control (SVC) in a converging-diverging nozzle with a rectangular cross-section is discussed as a fluidic thrust vectoring (FTV) method. The interaction between the primary nozzle flow and the secondary jet is examined using experiments and numerical simulations. The relationships between FTV parameters [nozzle pressure ratio (NPR) and secondary jet pressure ratio (SPR)] and FTV performance (thrust pitching angle and thrust pitching moment) are investigated. The experiments are conducted with an NPR of up to 10 and an SPR of up to 2.7. Numerical simulations of the nozzle flow are performed using a Navier-Stokes solver with input parameters set to match the experimental conditions. The thrust pitching angle and moment computed from the force-moment balance are used to evaluate FTV performance. The experiment and numerical results indicate that the FTV parameters (NPR and SPR) directly affect FTV performance. Conventionally, FTV performance evaluated by the common method using thrust pitching angle is highly dependent on the location of evaluation. Hence, in this study, we show that the thrust pitching moment, a parameter which is independent of the location, is the appropriate figure of merit to evaluate the performance of FTV systems.

  19. Investigation of injection molding of orthogonal fluidic connector for microfluidic devices

    Science.gov (United States)

    Xu, Zheng; Cao, Dong; Zhao, Wei; Song, Man-cang; Liu, Jun-shan

    2017-02-01

    Orthogonal fluidic connections are essential for developing multilayered microfluidic devices. At present, most orthogonal connectors are realized by a horizontal channel and a vertical channel in different plates. Therefore, some extra alignment and adhesion processes for precise plate assembly are required. In this paper, the method of injection molding is proposed to make a one-body-type orthogonal connector in a single plastic plate. The connector was composed of a cantilevered tube and the other in the substrate. An injection mold was developed in which a side core-pulling mechanism and an ejection mechanism of push-pipes were combined to form the mold for an orthogonal connector. Both the type and the location of gate were optimized for the mold. The results showed that the fan gate in the middle position of the plate was the most suitable in term of both defect control and practicability. The effect of melt temperature was numerically investigated and then verified experimentally. With the optimized parameters, the relative length and the relative wall thickness of a cantilevered tube in the plastic part can reach 98.89% and 99.80%, respectively. Furthermore, using the plastic part as a cover plate, a three-layer plastic microfluidic device was conveniently fabricated for electrochemical detection.

  20. Preliminary Evaluation of a Nest Usage Sensor to Detect Double Nest Occupations of Laying Hens

    Directory of Open Access Journals (Sweden)

    Mauro Zaninelli

    2015-01-01

    Full Text Available Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens’ welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage “sensor”, based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

  1. Preliminary evaluation of a nest usage sensor to detect double nest occupations of laying hens.

    Science.gov (United States)

    Zaninelli, Mauro; Costa, Annamaria; Tangorra, Francesco Maria; Rossi, Luciana; Agazzi, Alessandro; Savoini, Giovanni

    2015-01-26

    Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens' welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage "sensor", based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

  2. CyNEST: a maintainable Cython-based interface for the NEST simulator

    Directory of Open Access Journals (Sweden)

    Yury V. Zaytsev

    2014-03-01

    Full Text Available NEST is a simulator for large-scale networks of spiking point neuron models (Gewaltig and Diesmann, 2007. Originally, simulations were controlled via the Simulation Language Interpreter (SLI, a built-in scripting facility implementing a language derived from PostScript (Adobe Systems, 1999. The introduction of PyNEST (Eppler et al., 2008, the Python interface for NEST, enabled users to control simulations using Python. As the majority of NEST users found PyNEST easier to use and to combine with other applications, it immediately displaced SLI as the default NEST interface.However, developing and maintaining PyNEST has become increasingly difficult over time. This is partly because adding new features requires writing low-level C++ code intermixed with calls to the Python / C API, which is unrewarding. Moreover, the Python / C API evolves with each new version of Python, which results in a proliferation of version-dependent code branches.In this contribution we present the re-implementation of PyNEST in the Cython language, a superset of Python that additionally supports the declaration of C/C++ types for variables and class attributes, and provides a convenient foreign function interface (FFI for invoking C/C++ routines (Behnel et al., 2011. Code generation via Cython allows the production of smaller and more maintainable bindings, including increased compatibility with all supported Python releases without additional burden for NEST developers. Furthermore, this novel approach opens up the possibility to support alternative implementations of the Python language at no cost given a functional Cython back-end for the corresponding implementation, and also enables cross-compilation of Python bindings for embedded systems and supercomputers alike.

  3. Ants' learning of nest entrance characteristics (Hymenoptera, Formicidae).

    Science.gov (United States)

    Cammaerts, M C

    2014-02-01

    Young workers, experimentally removed from their nest and set in front of it, are not very good at finding the nest entrance and entering the nest. I examined how young ants learn their nest entrance characteristics, dealing only with the entrance sensu stricto, not with its vicinity. I observed that young ants have the innate behavior of trying to exit and re-enter their nest. I found that they are imprinted with the nest entrance odor while they are still living inside their nest and that they learn the visual aspect of their nest entrances, thanks to operant conditioning, when they exit their nest and succeed in re-entering in the course of their first short trips outside.

  4. Nest sharing under semi-natural conditions in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2012-01-01

    problems to laying hens, and egg production may also be negatively affected. Understanding what causes this difference in nest location selection may provide solutions to the problems associated with simultaneous nest sharing. The aims were to investigate whether a commercial strain of laying hens normally...... daily of each nest with regard to number of eggs, position, and materials used. On five mornings nesting behaviour was observed. Nest sharing occurred on all but the first 5 days of egg-laying. The majority of hens (n = 14) chose to visit an occupied nest at least once, but no hens exclusively used......Under natural conditions, the feral hen (Gallus gallus domesticus) will choose a nest location away from the flock, whereas under commercial conditions, the domestic hen will often choose the same nest as other hens have used or are still using. Simultaneous nest sharing causes several welfare...

  5. Crossings and nestings in colored set partitions

    CERN Document Server

    Marberg, Eric

    2012-01-01

    Several years ago, Chen, Deng, Du, Stanley, and Yan introduced the notion of $k$-crossings and $k$-nestings for set partitions, and proved that the sizes of the largest $k$-crossings and $k$-nestings in the partitions of an $n$-set possess a symmetric joint distribution. The present work extends these results to $r$-colored set partitions, by which we mean set partitions whose arcs are labeled by an $r$-element set. A $k$-crossing or $k$-nesting in this context is a sequence or arcs, all with the same color, which form a $k$-crossing or $k$-nesting in the usual sense. To prove our extension, we produce a bijection from $r$-colored set partitions to certain sequences of $r$-partite partitions, which in the uncolored case specializes to a novel description of the map from set partitions to vacillating tableaux given by Chen et al. Among other applications, we explain how our construction implies recent results of Chen and Guo on colored matchings, and also an analogous symmetric joint distribution of crossings ...

  6. A Serialization Graph Construction for Nested Transactions

    Science.gov (United States)

    1990-02-01

    allowing replacement of entire subtrees of nested activity by single actions as well as the reordering of actions in a history . Also, they do not...systems. 28 [11] N. Lynch, M. Merritt, W. Weihl, and A. Fekete. A theory of atomic transactions. In International Conference on Database Theory, Bruges

  7. Collective fluid mechanics of honeybee nest ventilation

    Science.gov (United States)

    Gravish, Nick; Combes, Stacey; Wood, Robert J.; Peters, Jacob

    2014-11-01

    Honeybees thermoregulate their brood in the warm summer months by collectively fanning their wings and creating air flow through the nest. During nest ventilation workers flap their wings in close proximity in which wings continuously operate in unsteady oncoming flows (i.e. the wake of neighboring worker bees) and near the ground. The fluid mechanics of this collective aerodynamic phenomena are unstudied and may play an important role in the physiology of colony life. We have performed field and laboratory observations of the nest ventilation wing kinematics and air flow generated by individuals and groups of honeybee workers. Inspired from these field observations we describe here a robotic model system to study collective flapping wing aerodynamics. We microfabricate arrays of 1.4 cm long flapping wings and observe the air flow generated by arrays of two or more fanning robotic wings. We vary phase, frequency, and separation distance among wings and find that net output flow is enhanced when wings operate at the appropriate phase-distance relationship to catch shed vortices from neighboring wings. These results suggest that by varying position within the fanning array honeybee workers may benefit from collective aerodynamic interactions during nest ventilation.

  8. Activity patterns of nesting Mexican Spotted Owls

    Science.gov (United States)

    David K. Delaney; Teryl G. Grubb; Paul Beier

    1999-01-01

    We collected 2,665 hr of behavioral information using video surveillance on 19 Mexican Spotted Owl (Strix occidentalis lucida) pairs between 25 April and 26 July 1996. Prey deliveries per day increased as the nesting season progressed, with an average of 2.68 prey deliveries during incubation, 4.10 items during brooding, and 4.51 items during the...

  9. Field guide to red tree vole nests

    Science.gov (United States)

    Damon B. Lesmeister; James K. Swingle

    2017-01-01

    Surveys for red tree vole (Arborimus longicaudus) nests require tree climbing because the species is a highly specialized arboreal rodent that live in the tree canopy of coniferous forests in western Oregon and northwestern California. Tree voles are associated with old coniferous forest (≥80 years old) that are structurally complex, but are often...

  10. A catalog of Louisiana's nesting seabird colonies

    Science.gov (United States)

    Fontenot, William R.; Cardiff, Steve W.; DeMay, Richard A.; Dittmann, Donna L.; Hartley, Stephen B.; Jeske, Clinton W.; Lorenz, Nicole; Michot, Thomas C.; Purrington, Robert Dan; Seymour, Michael; Vermillion, William G.

    2012-01-01

    Summarizing his colonial nesting waterbird survey experiences along the northern coast of the Gulf of Mexico in a paper presented to the Colonial Waterbird Group of the Waterbird Society (Portnoy 1978), bird biologist John W. Portnoy stated, “This huge concentration of nesting waterbirds, restricted almost entirely to the wetlands and estuaries of southern Louisiana, is unmatched in all of North America; for example, a 1975 inventory of wading birds along the Atlantic Coast from Maine to Florida [Custer and Osborn, in press], tallied 250,000 breeding [waterbirds] of 14 species, in contrast with the 650,000 birds of 15 species just from Sabine Pass to Mobile Bay.” The “650,000 birds” to which Portnoy referred, were tallied by him in a 1976 survey of coastal Louisiana, Mississippi, and Alabama (see below, under “Major Surveys” section). According to the National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-82 (Spendelow and Patton 1988), the percentages of the total U.S. populations of Laughing Gull (11%), Forster's Tern (52%), Royal Tern (16%), Sandwich Tern (77%), and Black Skimmer (44%) which annually nest in Louisiana are significant – perhaps crucially so in the cases of Forster's Tern, Sandwich Tern, and Black Skimmer. Nearly three decades after Spendelow and Patton's determinations above, coastal Louisiana still stands out as the major center of colonial wading bird and seabird nesting in all of the United States. Within those three intervening decades, however, the

  11. Nested Dissection Interface Reconstruction in Pececillo

    Energy Technology Data Exchange (ETDEWEB)

    Jibben, Zechariah Joel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    A nested dissection method for interface reconstruction in a volume tracking framework has been implemented in Pececillo. This method provides a significant improvement over the traditional onion-skin method, which does not appropriately handle T-shaped multimaterial intersections and dynamic contact lines present in additive manufacturing simulations. The resulting implementation lays the groundwork for further re- search in numerical contact angle estimates.

  12. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Northwest Arctic, Alaska: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in Northwest Arctic, Alaska. Vector points in this data set represent locations of...

  13. Nesting Loggerhead Sea Turtle Activity Report 2000 and 1980-2000 Nesting Summary

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper presents results from the 8th Annual Study (using Army Corp of Engineers funds) of nesting by the Atlantic Loggerhead sea turtle (Caretta caretta) along...

  14. Rhode Island, Connecticut, New York, and New Jersey ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector points in this...

  15. Exceptional sea turtle nest records in 2011 suggest an underestimated nesting potential in Sicily (Italy

    Directory of Open Access Journals (Sweden)

    Paolo Casale

    2012-07-01

    Full Text Available We report seven nesting events by loggerhead sea turtles in Sicily (Italy in 2011. In comparison to past records, this number is relatively high and may be at least in part due to an awareness campaign carried out in 2011 to solicit such reports. This suggests that Sicily may host a much higher nesting activity than previously thought and higher monitoring effort is recommended, especially in certain coastal tracts. Sand temperatures and incubation periods indicate that the beaches monitored so far in the southern coast are not optimal for development, resulting in low hatching success, and produce a majority of males. Five 2011 nests and two past nests from the same area had mtDNA haplotype CC-A2.1, the most common in the Mediterranean.

  16. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Southern California: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting and roosting gulls, terns, seabirds, shorebirds, and T/E species in Southern California....

  17. Timing of nest vegetation measurement may obscure adaptive significance of nest-site characteristics: A simulation study.

    Science.gov (United States)

    McConnell, Mark D; Monroe, Adrian P; Burger, Loren Wes; Martin, James A

    2017-02-01

    Advances in understanding avian nesting ecology are hindered by a prevalent lack of agreement between nest-site characteristics and fitness metrics such as nest success. We posit this is a result of inconsistent and improper timing of nest-site vegetation measurements. Therefore, we evaluated how the timing of nest vegetation measurement influences the estimated effects of vegetation structure on nest survival. We simulated phenological changes in nest-site vegetation growth over a typical nesting season and modeled how the timing of measuring that vegetation, relative to nest fate, creates bias in conclusions regarding its influence on nest survival. We modeled the bias associated with four methods of measuring nest-site vegetation: Method 1-measuring at nest initiation, Method 2-measuring at nest termination regardless of fate, Method 3-measuring at nest termination for successful nests and at estimated completion for unsuccessful nests, and Method 4-measuring at nest termination regardless of fate while also accounting for initiation date. We quantified and compared bias for each method for varying simulated effects, ranked models for each method using AIC, and calculated the proportion of simulations in which each model (measurement method) was selected as the best model. Our results indicate that the risk of drawing an erroneous or spurious conclusion was present in all methods but greater with Method 2 which is the most common method reported in the literature. Methods 1 and 3 were similarly less biased. Method 4 provided no additional value as bias was similar to Method 2 for all scenarios. While Method 1 is seldom practical to collect in the field, Method 3 is logistically practical and minimizes inherent bias. Implementation of Method 3 will facilitate estimating the effect of nest-site vegetation on survival, in the least biased way, and allow reliable conclusions to be drawn.

  18. Does nest site availability limit the density of hole nesting birds in small woodland patches?

    Directory of Open Access Journals (Sweden)

    J. Loman

    2006-11-01

    Full Text Available By providing nest boxes, previous studies have shown that nest sites are in short supply and limit the populations of several small passerines, including the Great Tit Parus major, the Blue Tit P. caeruleus, and the Pied Flycatcher Ficedula hypoleuca. Can this influence their distribution over a range of small woodland patch sizes in a heterogeneous landscape? To investigate this, a study was conducted in a heterogeneous agricultural landscape, with a mixture of wooded patches and cropped fields, in southern Sweden. The descriptive part of the study involved mapping territories of the three species in 135 patches. These species avoided small (<1 ha, Pied Flycatcher or very small (<0.2 ha, the two tit species forest patches in this landscape. In an experimental part, a subset of 34 patches, 0.01 to 24 ha in size was used. Territories were mapped in a first year as a control. In a second year, patches were matched by size and vegetation and nest-boxes were provided in one patch of each pair. Territories were again mapped. Providing nestboxes increased the density of breeding Great Tits in patches of all sizes and expanded their use of very small patches. The nest-boxes increased the density of Pied Flycatchers in large patches but not in small patches. So, is the lack of territories in small patches due to shortage of nest sites? The outcome of the experiment suggests nest site limitation as a cause of the observed Great Tit discrimination against very small habitat patches. The lack of Pied Flycatchers in small patches must however have another basis than lack of nest sites. The effect of providing nest-boxes on Blue Tit distribution was inconclusive.

  19. Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

    Science.gov (United States)

    Lovich, Jeffrey E.; Agha, Mickey; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Ennen, Joshua R.; Arundel, Terry R.; Austin, Meaghan

    2014-01-01

    Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

  20. Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

    Directory of Open Access Journals (Sweden)

    Kohei Tanaka

    Full Text Available Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1 covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes, and 2 open nests, in which eggs are exposed in the nest and brooded (as in most birds. Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1 covered nests are likely the primitive condition for dinosaurs (and probably archosaurs, and 2 open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment

  1. Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

    Science.gov (United States)

    Tanaka, Kohei; Zelenitsky, Darla K; Therrien, François

    2015-01-01

    Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests

  2. Nest site preferences of the Woodlark (Lullula arborea) and its association with artificial nest predation

    Science.gov (United States)

    Buehler, Roman; Bosco, Laura; Arlettaz, Raphaël; Jacot, Alain

    2017-01-01

    The Woodlark is an insectivorous bird, which is listed as a priority species in Switzerland. In Valais, a stronghold of this species in the country, the birds breed in intensively managed vineyards and show a preference for parcels with ground vegetation during territory establishment. As a ground-breeder, the species is highly vulnerable to nest predation by avian and mammal predators. The aims of our study were firstly to investigate nest site preferences of the woodlark within vineyards and secondly to compare the predation risk of artificial nests dependent of ground vegetation structure. Our results point out that the Woodlark prefers patches of tall and dense ground cover within vegetated vineyard parcels and avoids parcels that have been treated with herbicides. In a follow-up experiment we conducted a study comparing the predation rate of artificial nests between bare parcels (40% vegetated area). Artificial nests equipped with one quail egg were distributed pairwise between two adjacent parcels that fulfilled the upper criteria and were monitored by trail cameras during 10-12 days. Predation rate was generally low (4 predation events) and only occurred in bare parcels. These data indicate that conspicuousness of avian nests may be decreased in vegetated parcels and that the amount of vegetation can lower the predation risk on ground breeding birds - another indication for the importance of ground vegetation for a successful conservation of the endangered Woodlark in Swiss vineyards.

  3. Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil.

    Science.gov (United States)

    Buschini, M L T; Niesing, F; Wolff, L L

    2006-08-01

    This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause), and delayed development (with diapause during winter). Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

  4. Nesting biology of Trypoxylon (Trypargilum lactitarse Saussure (Hymenoptera, Crabronidae in trap-nests in Southern Brazil

    Directory of Open Access Journals (Sweden)

    M. L. T. Buschini

    Full Text Available This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause, and delayed development (with diapause during winter. Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

  5. Nest predators, nest-site selection andnest success ofthe Emei Shan Liocichla (Liocichla omeiensis), a vulnerable babbler endemic tosouthwestern China

    Institute of Scientific and Technical Information of China (English)

    Yiqiang Fu; Benping Chen; Simon D Dowell; Zhengwang Zhang

    2016-01-01

    Background: The Emei Shan Liocichla (Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwest-ern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success. Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates (DSR). Nest success was calculated using the Mayifeld method. Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564± 0.0091 (95 % CI 0.9346–0.9711) (n= 40), while the total nest success was 27.5 %. We identiifed four categories of predators in 10 nest predation events, i.e. squirrels (n= 5), snakes (n= 3), raptors (n= 1) and wasps (n= 1). We found that: (1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla, (2) tree cover, bamboo cover, liana abun-dance and distance to forest edge or gap were the most important variables affecting nest-site selection of this spe-cies, and (3) the nest-site-selection variables we measured appeared not to be positively associated with nest success. Conclusions: Our ifndings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adap-tive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.

  6. A micro-fluidic treadmill for observing suspended plankton in the lab

    Science.gov (United States)

    Jaffe, J. S.; Laxton, B.; Garwood, J. C.; Franks, P. J. S.; Roberts, P. L.

    2016-02-01

    A significant obstacle to laboratory studies of interactions between small organisms ( mm) and their fluid environment is our ability to obtain high-resolution images while allowing freedom of motion. This is because as the organisms sink, they will often move out of the field of view of the observation system. One solution to this problem is to impose a water circulation pattern that preserves their location relative to the camera system while imaging the organisms away from the glass walls. To accomplish this we have designed and created a plankton treadmill. Our computer-controlled system consists of a digital video camera attached to a macro or microscope and a micro-fluidic pump whose flow is regulated to maintain a suspended organism's position relative to the field of view. Organisms are detected and tracked in real time in the video frames, allowing a control algorithm to compensate for any vertical movement by adjusting the flow. The flow control can be manually adjusted using on-screen controls, semi-automatically adjusted to allow the user to select a particular organism to be tracked or fully automatic through the use of classification and tracking algorithms. Experiments with a simple cm-sized cuvette and a number of organisms that are both positively and negatively buoyant have demonstrated the success of the system in permitting longer observation times than would be possible in the absence of a controlled-flow environment. The subjects were observed using a new dual-view, holographic imaging system that provides 3-dimensional microscopic observations with relatively isotropic resolution. We will present the system design, construction, the control algorithm, and some images obtained with the holographic system, demonstrating its effectiveness. Small particles seeded into the flow clearly show the 3D flow fields around the subjects as they freely sink or swim.

  7. Surface Tension Directed Fluidic Self-Assembly of Semiconductor Chips across Length Scales and Material Boundaries

    Directory of Open Access Journals (Sweden)

    Shantonu Biswas

    2016-03-01

    Full Text Available This publication provides an overview and discusses some challenges of surface tension directed fluidic self-assembly of semiconductor chips which are transported in a liquid medium. The discussion is limited to surface tension directed self-assembly where the capture, alignment, and electrical connection process is driven by the surface free energy of molten solder bumps where the authors have made a contribution. The general context is to develop a massively parallel and scalable assembly process to overcome some of the limitations of current robotic pick and place and serial wire bonding concepts. The following parts will be discussed: (2 Single-step assembly of LED arrays containing a repetition of a single component type; (3 Multi-step assembly of more than one component type adding a sequence and geometrical shape confinement to the basic concept to build more complex structures; demonstrators contain (3.1 self-packaging surface mount devices, and (3.2 multi-chip assemblies with unique angular orientation. Subsequently, measures are discussed (4 to enable the assembly of microscopic chips (10 μm–1 mm; a different transport method is introduced; demonstrators include the assembly of photovoltaic modules containing microscopic silicon tiles. Finally, (5 the extension to enable large area assembly is presented; a first reel-to-reel assembly machine is realized; the machine is applied to the field of solid state lighting and the emerging field of stretchable electronics which requires the assembly and electrical connection of semiconductor devices over exceedingly large area substrates.

  8. Novel fluidic packaging of gimbal-less MEMS mirrors for increased optical resolution and overall performance

    Science.gov (United States)

    Milanovic, Veljko; Kasturi, Abhishek; Yang, James

    2016-05-01

    Gimbal-less two-axis quasistatic MEMS mirrors have the ability to reflect optical beams to arbitrary positions and with arbitrary velocity. This technology has become established in many applications including laser based tracking, 3D scanning, biomedical imaging, free-space communication, and LiDAR. However, for certain defense applications, the total angle × diameter product, or the mirror's effective achievable resolution (θ*D product), has not been large enough to address requirements for agile steering in large fields of regard and with a low diffraction-limited beam divergence. Two key limitations have been the relatively low forces available in electrostatic combdrive actuators and the susceptibility of large-diameter MEMS mirrors to shock and vibrations. In this work, we demonstrate that these same MEMS mirrors can have dramatically increased performance when fully immersed and packaged in dielectric liquids with highly favorable torque-increasing, damping-increasing, and optical gain-increasing properties. The rotating electrostatic combdrive has its torque multiplied by liquid's relative permittivity of ~2.5. Furthermore, by selecting the appropriate fluid viscosity, quality factor of the device is reduced and structural damping is tuned to near critical damping. Finally, the increased scan angle due to the ~1.5-1.7 index of refraction of the fluid is an additional benefit. These numerous benefits of the fluidic packaging enabled us to double and in some cases triple the previously achieved θ*D product of two-axis quasistatic MEMS mirrors while still maintaining speeds applicable for above mentioned applications. One of the most exciting benefits of the packaging methodologies is that the damping dramatically increases shock and vibration tolerance, which will be tested next.

  9. An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications.

    Science.gov (United States)

    Mansoor, Mohtashim; Haneef, Ibraheem; Akhtar, Suhail; Rafiq, Muhammad Aftab; De Luca, Andrea; Ali, Syed Zeeshan; Udrea, Florin

    2016-11-04

    An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA-0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C-1.79 mV/°C in the range 20-300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(Vexcit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min)(-0.1) in the tested range of 0-4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries.

  10. Psychicones: Visual Traces of the Soul in Late Nineteenth-Century Fluidic Photography

    Science.gov (United States)

    Pethes, Nicolas

    2016-01-01

    The article discusses attempts to visualise the soul on photographic plates at the end of the nineteenth century, as conducted by the French physician Hippolyte Baraduc in Paris. Although Baraduc refers to earlier experiments on fluidic photography in his book on The Human Soul (1896) and is usually mentioned as a precursor to parapsychological thought photography of the twentieth century, his work is presented as a genuine attempt at photographic soul-catching. Rather than producing mimetic representations of thoughts and imaginations, Baraduc claims to present the vital radiation of the psyche itself and therefore calls the images he produces psychicones. The article first discusses the difference between this method of soul photography and other kinds of occult media technologies of the time, emphasising the significance of its non-mimetic, abstract character: since the soul itself was considered an abstract entity, abstract traces seemed all the more convincing to the contemporary audience. Secondly, the article shows how the technological agency of photography allowed Baraduc’s psychicones to be tied into related discourses in medicine and psychology. Insofar as the photographic plates displayed actual visual traces, Baraduc and his followers no longer considered hallucinations illusionary and pathological but emphasised the physical reality and normality of imagination. Yet, the greatest influence of soul photography was not on science but on art. As the third part of the paper argues, the abstract shapes on Baraduc’s plates provided inspiration for contemporary avant-garde aesthetics, for example, Kandinsky’s abstract paintings and the random streams of consciousness in surrealistic literature. PMID:27292323

  11. An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications

    Directory of Open Access Journals (Sweden)

    Mohtashim Mansoor

    2016-11-01

    Full Text Available An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors, a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA–0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C–1.79 mV/°C in the range 20–300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(Vexcit kPa with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min−0.1 in the tested range of 0–4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries.

  12. Patterns of artificial nest depredation in a large floodplain forest

    Science.gov (United States)

    Knutson, Melinda G.; Gutreuter, Steven J.; Klaas, Erwin E.

    2000-01-01

    We used artificial bird nests to examine the relative effects of local habitat features and the surrounding landscape on the probability of songbird nest depredation in floodplain forests of the Upper Mississippi River. We found that the probability of depredation increased with size of floodplain forest plots. In small plots, the probability of depredation tended to increase away from the forest edge. Small patches of floodplain forest within a large river system can provide valuable nesting habitat for songbirds. We suggest that depredation pressure may be lower due to isolation effects. The probability of nest depredation increased with increasing canopy cover surrounding the nest tree and decreasing cover around the nest. Managers seeking to discourage nest predators in floodplain forests should consider managing for habitats that supply dense cover for nest concealment and an open tree canopy.

  13. 2012 waterfowl nesting study at Fish Springs National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report on a 2012 duck nesting study at Fish Springs National Wildlife Refuge, where nest drag plots were surveyed within management units. Duck production estimates...

  14. 1972 American Eagle Nest Survey of the Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1972 nesting season for the Bald Eagle in the Chesapeake area to include Virginia and Maryland. The 1972 nesting season for the Bald Eagle in the...

  15. 1971 American Eagle Nest Survey of the Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1971 nesting season for the Bald Eagle in the Chesapeake area to include Virginia and Maryland. In general, the Chesapeake Bay region nesting...

  16. Potential Kittlitz's Murrelet Nesting Habitat in North America

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Using nest records and locations to identify landscape-scale parameters (distance to coast, elevation, slope, and land cover) that provide potential nesting habitat,...

  17. DISPERSAL OF SEEDS AS NEST MATERIAL BY THE CACTUS WREN

    Science.gov (United States)

    Cactus wren (Campylorhynchus brunneicapillus) nests from the southern Chihuahuan Desert contained viable seeds of grasses, forbs, and shrubs. The most common plants used as construction material in these nests were Muhlenbergia porteri, Boerhavia spicata, and the alien grass Era...

  18. Seedskadee National Wildlife Refuge : duck nesting success report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a report summarizing the fourth consecutive year of data collection for duck nesting success at Seedskadee National Wildlife Refuge during the 1990 nesting...

  19. Nest sites selection by sympatric cavity-nesting birds in miombo woodlands

    Directory of Open Access Journals (Sweden)

    Vincent R. Nyirenda

    2016-03-01

    Full Text Available Deforestation and habitat fragmentation have long been known as drivers of wildlife depletion but information on their specific impacts on cavity-nesting birds in the miombo woodlands has been lacking. A comparative study of disturbed and undisturbed sites was conducted in miombo woodlands of Zambia to assess impacts of environmental stressors on birds. Foot patrols were employed to locate, identify and count host trees and cavities for cavity-nesting birds on twenty 200 m × 200 m sample plots. Undisturbed forests had three times more cavities (the nesting sites for birds, while there were 24.6% fewer abandoned cavities in undisturbed forests than in disturbed forests. The rate of cavity abandonment was about twice as high in human-dominated forests compared to undisturbed forests (61.3% c.f. 31.9%. Cavity-nesting birds preferred larger (> 36.0 cm diameter at breast height and taller (> 5.0 m trees for nest placement, especially in human-dominated forests. A number of cavity-nesting birds preferred Brachystegia spiciformis (zebrawood, Julbernadia paniculata (munsa, Parinari curatellifolia (mobola-plum and Uapaca kirkiana (mahobohobo as host trees to 14 other miombo tree species. Arnot’s Chat (Myrmecocichla arnoti had a wider selection of host trees for cavity-nesting than the other 40 cavity-nesting birds in the study areas. Anthropogenic activities such as uncontrolled firewood collection, wild fires, logging, and land clearing for agriculture negatively influenced wood abundance and diversity, with potential implications for persistence of cavity-nesting birds. The negative impacts of anthropogenic activities could be counteracted by conservation strategies such as implementation of sound forest policies, integrative land use practices, sustainable livelihood security and stakeholders’ awareness of the need to safeguard forest-dependent avifauna.Conservation implications: This comparative study unravels specific anthropogenic impacts on

  20. Nesting biology of four Tetrapedia species in trap-nests (Hymenoptera: Apidae: Tetrapediini).

    Science.gov (United States)

    Camillo, Evandro

    2005-01-01

    The nests used in this study were obtained from trap-nests (tubes of cardboard and cut bamboo stems) placed on Santa Carlota Farm (Itaoca Section-IS, Santana Section-SS and Cerrado-Ce), Cajuru, SP, Brazil. The number of nests and corresponding species obtained were as follows: 516 nests of T. curvitarsis, 104 of T. rugulosa, 399 of T. diversipes and 98 of T. gamfaloi. The most abundant species from SS and Ce was T. curvitarsis, and from IS it was T. diversipes. In general, most nests were collected during the hot and wet season (September to April). The nests were constructed with sand and an oily substance, and a single female established them. The cells were constructed in a linear series, sometimes followed by a vestibular cell. The number of brood cells ranged from 1 to 10 in T. curvitarsis (n=200), and in T. garofaloi (n-51), from 1 to 8 (n-30) in T. rugulosa, and from 1 to 6 (n=37) in T. diversipes. The pollen mass (pollen + oily substance) contained a hollow, sometimes divided by a transverse ridge, on the exposed face of the pollen mass. The egg was vertically positioned in the lower part of the hollow. At times, the closing of a cell was initiated before provisioning was completed, with a construction of a collar at the cell limit. In some nests the final cellular partition also acted as a closure plug. Females began activities at 6:18 a.m. and ended between 3:31 and 6:26 p.m. Some females (T. curvitarsis, T. rugiulosa and T. ganrfaloi) did not spend the nights at their nests, returning to them only the following morning with additional material. In general, the development period (for males and females) was greater in nests collected near the end of the hot and wet season than it was for nests collected in other months. Sex ratios for each species were as follows: T. curvitarsis. 1:1: T. rugulosa, 1.6:1 female; T. diversipes, 1.9:1: T. garofaloi, 2.8:1. Males and females of T. diversipes exhibited statistically similar sizes and in the other three species

  1. Comparing coefficients of nested nonlinear probability models

    DEFF Research Database (Denmark)

    Kohler, Ulrich; Karlson, Kristian Bernt; Holm, Anders

    2011-01-01

    In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general decomposi......In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general...... decomposition method that is unaffected by the rescaling or attenuation bias that arise in cross-model comparisons in nonlinear models. It recovers the degree to which a control variable, Z, mediates or explains the relationship between X and a latent outcome variable, Y*, underlying the nonlinear probability...

  2. Broadband DOA Estimation Based on Nested Arrays

    Directory of Open Access Journals (Sweden)

    Zhi-bo Shen

    2015-01-01

    Full Text Available Direction of arrival (DOA estimation is a crucial problem in electronic reconnaissance. A novel broadband DOA estimation method utilizing nested arrays is devised in this paper, which is capable of estimating the frequencies and DOAs of multiple narrowband signals in broadbands, even though they may have different carrier frequencies. The proposed method converts the DOA estimation of multiple signals with different frequencies into the spatial frequency estimation. Then, the DOAs and frequencies are pair matched by sparse recovery. It is possible to significantly increase the degrees of freedom (DOF with the nested arrays and the number of sources can be more than that of sensor array. In addition, the method can achieve high estimation precision without the two-dimensional search process in frequency and angle domain. The validity of the proposed method is verified by theoretic analysis and simulation results.

  3. Nested partitions method, theory and applications

    CERN Document Server

    Shi, Leyuan

    2009-01-01

    There is increasing need to solve large-scale complex optimization problems in a wide variety of science and engineering applications, including designing telecommunication networks for multimedia transmission, planning and scheduling problems in manufacturing and military operations, or designing nanoscale devices and systems. Advances in technology and information systems have made such optimization problems more and more complicated in terms of size and uncertainty. Nested Partitions Method, Theory and Applications provides a cutting-edge research tool to use for large-scale, complex systems optimization. The Nested Partitions (NP) framework is an innovative mix of traditional optimization methodology and probabilistic assumptions. An important feature of the NP framework is that it combines many well-known optimization techniques, including dynamic programming, mixed integer programming, genetic algorithms and tabu search, while also integrating many problem-specific local search heuristics. The book uses...

  4. Recursive Polynomial Remainder Sequence and the Nested Subresultants

    OpenAIRE

    Terui, Akira

    2008-01-01

    We give two new expressions of subresultants, nested subresultant and reduced nested subresultant, for the recursive polynomial remainder sequence (PRS) which has been introduced by the author. The reduced nested subresultant reduces the size of the subresultant matrix drastically compared with the recursive subresultant proposed by the authors before, hence it is much more useful for investigation of the recursive PRS. Finally, we discuss usage of the reduced nested subresultant in approxima...

  5. Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

    Science.gov (United States)

    Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

    2014-09-01

    This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing.

  6. Imperfect nesting in unconventional density waves

    Science.gov (United States)

    Dóra, Balázs; Virosztek, Attila; Maki, Kazumi

    2002-03-01

    Recently, we have shown that unconventional charge density wave (UCDW) is the most likely candidate for the unidentified low-temperature phase (LTP) in α-(ET)2 salts. In particular, UCDW describes reasonably well the temperature dependence of the threshold electric field of LTP in α-(ET)2KHg(SCN)4. Here, we shall show that the imperfect nesting in UCDW is crucial to further improve the theoretical description of the threshold electric field.

  7. Structural relations between nested harmonic sums

    Energy Technology Data Exchange (ETDEWEB)

    Bluemlein, J.

    2008-07-15

    We describe the structural relations between nested harmonic sums emerging in the description of physical single scale quantities up to the 3-loop level in renormalizable gauge field theories. These are weight w=6 harmonic sums. We identify universal basic functions which allow to describe a large class of physical quantities and derive their complex analysis. For the 3-loop QCD Wilson coefficients 35 basic functions are required, whereas a subset of 15 describes the 3-loop anomalous dimensions. (orig.)

  8. Nested Dissection Interface Reconstruction in Pececillo

    Energy Technology Data Exchange (ETDEWEB)

    Jibben, Zechariah Joel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division; Carlson, Neil N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division; Francois, Marianne M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division

    2016-09-13

    A nested dissection method for interface reconstruction in a volume tracking framework has been implemented in Pececillo, a mini-app for Truchas, which is the ASC code for casting and additive manufacturing. This method provides a significant improvement over the traditional onion-skin method, which does not appropriately handle T-shaped multimaterial intersections and dynamic contact lines present in additive manufacturing simulations. The resulting implementation lays the groundwork for further research in contact angle estimates and surface tension calculations.

  9. DIAMONDS: a new Bayesian nested sampling tool*

    Directory of Open Access Journals (Sweden)

    Corsaro Enrico

    2015-01-01

    Full Text Available In the context of high-quality asteroseismic data provided by the NASA Kepler Mission, we developed a new code, termed DIAMONDS (high-DImensional And multi-MOdal NesteD Sampling, for fast Bayesian parameter estimation and model comparison by means of the Nested Sampling Monte Carlo (NSMC algorithm, an efficient and powerful method very suitable for high-dimensional problems (like the peak bagging analysis of solar-like oscillations and multi-modal problems (i.e. problems that show multiple solutions. We applied the code to the peak bagging analysis of solar-like oscillations observed in a challenging F-type star. By means of DIAMONDS one is able to detect the different backgrounds in the power spectrum of the star (e.g. stellar granulation and faculae activity and to understand whether one or two oscillation peaks can be identified or not. In addition, we demonstrate a novel approach to peak bagging based on multi-modality, which is able to reduce significantly the number of free parameters involved in the peak bagging model. This novel approach is therefore of great interest for possible future automatization of the entire analysis technique.

  10. Understanding thermo-fluidic characteristics of a glass tube closed loop pulsating heat pipe: flow patterns and fluid oscillations

    Science.gov (United States)

    Karthikeyan, V. K.; Ramachandran, K.; Pillai, B. C.; Brusly Solomon, A.

    2015-12-01

    An experimental program has been carried out to understand the thermo-fluidic characterization of deionized (DI) water charged closed loop pulsating heat pipe (CLPHP) with flow patterns and fluid oscillations. The CLPHP is examined under vertical and horizontal heating modes with varying heat power. The flow patterns along with fluid oscillations are correlated with thermal performance of the CLPHP. Further, the CLPHP with copper oxide nanofluid study is carried out to understand operational behavior of the device. Fast Fourier frequencies, average frequency of the internal fluid temperature are investigated. Several important features of CLPHP operation are identified by the visual study.

  11. Disposable micro-fluidic biosensor array for online parallelized cell adhesion kinetics analysis on quartz crystal resonators

    DEFF Research Database (Denmark)

    Cama, G.; Jacobs, T.; Dimaki, Maria

    2010-01-01

    In this contribution we present a new disposable micro-fluidic biosensor array for the online analysis of adherent Madin Darby canine kidney (MDCK-II) cells on quartz crystal resonators (QCRs). The device was conceived for the parallel cultivation of cells providing the same experimental conditions...... molding process was simulated in order to optimize the mold geometry and minimize the shrinkage and the warpage of the parts. MDCK-II cells were cultivated in the biosensor array. Parallel cultivation of cells on the gold surface of the QCRs led to first observations of the impact of the cell distribution...

  12. Effects of prescribed burns on wintering cavity-nesting birds

    Science.gov (United States)

    Heather L. Bateman; Margaret A. O' Connell

    2006-01-01

    Primary cavity-nesting birds play a critical role in forest ecosystems by excavating cavities later used by other birds and mammals as nesting or roosting sites. Several species of cavity-nesting birds are non-migratory residents and consequently subject to winter conditions. We conducted winter bird counts from 1998 to 2000 to examine the abundance and habitat...

  13. Nest Success of Gunnison Sage-Grouse in Colorado, USA.

    Directory of Open Access Journals (Sweden)

    Amy J Davis

    Full Text Available Gunnison Sage-Grouse (Centrocercus minimus is a species of concern for which little demographic information exists. To help fill this information gap, we investigated factors affecting nest success in two populations of Gunnison Sage-Grouse. We assessed the relative effects of (1 vegetation characteristics (e.g., shrub height, shrub cover, grass cover, and grass height, (2 temporal factors (e.g., year, timing of incubation initiation, and nest age, (3 precipitation, and (4 age of the nesting female (yearling or adult on nest success rates. We found 177 nests in the Gunnison Basin population (that contains 85-90% of the species from 2005-2010 and 20 nests in the San Miguel population (that contains < 10% of the species from 2007-2010. Temporal factors had the greatest impact on nest success compared to vegetation characteristics, precipitation, and female age. Nest success varied considerably among years ranging from 4.0%-60.2% in Gunnison Basin and from 12.9%- 51.9% in San Miguel. Nests that were initiated earlier in the breeding season had higher nest success (at least one egg hatches. Daily nest survival rates decreased during the course of incubation. None of the vegetation characteristics we examined were strongly related to nest success.

  14. Ant colonies prefer infected over uninfected nest sites

    DEFF Research Database (Denmark)

    Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley

    2014-01-01

    the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites...

  15. Communal nesting and kinship in degus (Octodon degus)

    Science.gov (United States)

    Ebensperger, Luis A.; Hurtado, María José; Soto-Gamboa, Mauricio; Lacey, Eileen A.; Chang, Ann T.

    Communal nesting is a fundamental component of many animal societies. Because the fitness consequences of this behavior vary with the relatedness among nest mates, understanding the kin structure of communally nesting groups is critical to understanding why such groups form. Observations of captive degus (Octodon degus) indicate that multiple females nest together, even when supplied with several nest boxes. To determine whether free-living degus also engage in communal nesting, we used radiotelemetry to monitor spatial relationships among adult females in a population of O. degus in central Chile. These analyses revealed that females formed stable associations of > 2-4 individuals, all of whom shared the same nest site at night. During the daytime, spatial overlap and frequency of social interactions were greatest among co-nesting females, suggesting that nesting associations represent distinct social units. To assess kinship among co-nesting females, we examined genotypic variation in our study animals at six microsatellite loci. These analyses indicated that mean pairwise relatedness among members of a nesting association (r=0.25) was significantly greater than that among randomly selected females (r=-0.03). Thus, communally nesting groups of degus are composed of female kin, making it possible for indirect as well as direct fitness benefits to contribute to sociality in this species.

  16. Trap-nests for stingless bees (Hymenoptera, Meliponini)

    NARCIS (Netherlands)

    Oliveira, Ricardo Caliari; Menezes, Cristiano; Egea Soares, Ademilson Espencer; Imperatriz Fonseca, Vera Lucia

    2013-01-01

    Most stingless bee species build their nests inside tree hollows. In this paper, we present trap-nest containers which simulate nesting cavities so as to attract swarms of stingless bees. Although regularly used by stingless bee beekeepers in Brazil, this technique to obtain new colonies has not yet

  17. Semantic Analysis of Virtual Classes and Nested Classes

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1999-01-01

    Virtual classes and nested classes are distinguishing features of BETA. Nested classes originated from Simula, but until recently they have not been part of main stream object- oriented languages. C++ has a restricted form of nested classes and they were included in Java 1.1. Virtual classes...... the central elements of the semantic analysis used in the Mjølner BETA compiler....

  18. A Local Characterization of Lie Homomorphisms of Nest Algebras

    Institute of Scientific and Technical Information of China (English)

    YANG Miao-xia; ZHANG Jian-hua

    2014-01-01

    In this paper, linear maps preserving Lie products at zero points on nest algebras are studied. It is proved that every linear map preserving Lie products at zero points on any finite nest algebra is a Lie homomorphism. As an application, the form of a linear bijection preserving Lie products at zero points between two finite nest algebras is obtained.

  19. An Architecture for Nested Transaction Support on Standard Database Systems

    NARCIS (Netherlands)

    Boertjes, E.M.; Grefen, P.W.P.J.; Vonk, J.; Apers, Peter M.G.

    Many applications dealing with complex processes require database support for nested transactions. Current commercial database systems lack this kind of support, offering flat, non-nested transactions only. This paper presents a three-layer architecture for implementing nested transaction support on

  20. Ground nesting in recultivated forest habitats - a study with artificial nests

    Energy Technology Data Exchange (ETDEWEB)

    Purger, J.J.; Meszaros, L.A.; Purger, D. [University of Pecs, Pecs (Hungary). Faculty of Science

    2004-01-01

    The study was carried out in the outskirts of the town of Pecs (southern Hungary) in a recultivated former coal mine. Bordered by Turkey Oak forests, this open area forms a wedge-shaped clearing in that woodland. Since trees and taller shrubs are rare in the area, it is mainly ground nesting bird species that occur in the clearing. In order to discover whether it is more advantageous to nest in the recultivated area (clearing) than in the nearby forest or at its edges, 150 artificial ground nests were constructed. On 7 May 2002, one quail egg and a plasticine egg of similar size were placed in each of the artificial nests. After a week it was found that 24% of nests in the clearing, 30% of those in the forest edge, and 44% of the ones inside the forest had suffered depredation. The proportions of damaged plasticine and quail eggs inside the forest and at the forest edge were similar, whereas the quail eggs in the clearings were significantly less damaged than plasticine eggs. Of all the experimental eggs, significantly more plasticine eggs (29%) were damaged than quail eggs (17%), which suggests that small-bodied predators are unable to break the quail eggs. 18% of the plasticine eggs attacked, and 72% of the quail eggs attacked were removed from the nest by the predator. Among the predators, small mammals were dominant in the clearing and inside the forest, and birds at the forest edge. Based on the predation of quail eggs, the survival chances of ground nests in the clearing are greater than at the forest edge or inside the forest.

  1. An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

    Directory of Open Access Journals (Sweden)

    Chang-Soo Kim

    2012-06-01

    Full Text Available Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide. Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc. to implement a viable component for in-line fluidic sensor systems.

  2. Changes in position and quality of preferred nest box: effects on nest box use by laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch; Nielsen, Birte L.

    2013-01-01

    Using laying hens, we investigated whether position of a nest box, both within the pen and relative to other nest boxes, influenced the preference for a nest box, and how a sudden and marked change to the preferred box influenced the use of nest boxes by the hens. Groups (n=12) of 15 Isa Warren...... revealed that some hens were location conservative, i.e. continued laying in a corner location (or as close to that as possible), whereas others were isolation conservative, i.e. continued laying in the most isolated nest box despite it being positioned in a different area of the pen....... hens were housed in pens, each with five identical nest boxes in different positions: Two single (in a corner or not) and a triplet of nest boxes (one of which in a corner). The use of nest boxes was determined by the number of eggs laid daily in each box. Three experiments, each lasting 10 days, were...

  3. Sharp-Tailed Grouse Nest Survival and Nest Predator Habitat Use in North Dakota’s Bakken Oil Field

    Science.gov (United States)

    2017-01-01

    Recent advancements in extraction technologies have resulted in rapid increases of gas and oil development across the United States and specifically in western North Dakota. This expansion of energy development has unknown influences on local wildlife populations and the ecological interactions within and among species. Our objectives for this study were to evaluate nest success and nest predator dynamics of sharp-tailed grouse (Tympanuchus phasianellus) in two study sites that represented areas of high and low energy development intensities in North Dakota. During the summers of 2012 and 2013, we monitored 163 grouse nests using radio telemetry. Of these, 90 nests also were monitored using miniature cameras to accurately determine nest fates and identify nest predators. We simultaneously conducted predator surveys using camera scent stations and occupancy modeling to estimate nest predator occurrence at each site. American badgers (Taxidea taxus) and striped skunks (Mephitis mephitis) were the primary nest predators, accounting for 56.7% of all video recorded nest depredations. Nests in our high intensity gas and oil area were 1.95 times more likely to succeed compared to our minimal intensity area. Camera monitored nests were 2.03 times more likely to succeed than non-camera monitored nests. Occupancy of mammalian nest predators was 6.9 times more likely in our study area of minimal gas and oil intensity compared to the high intensity area. Although only a correlative study, our results suggest energy development may alter the predator community, thereby increasing nest success for sharp-tailed grouse in areas of intense development, while adjacent areas may have increased predator occurrence and reduced nest success. Our study illustrates the potential influences of energy development on the nest predator—prey dynamics of sharp-tailed grouse in western North Dakota and the complexity of evaluating such impacts on wildlife. PMID:28081245

  4. Nest-site competition between invasive and native cavity nesting birds and its implication for conservation.

    Science.gov (United States)

    Charter, Motti; Izhaki, Ido; Ben Mocha, Yitzchak; Kark, Salit

    2016-10-01

    Nesting cavities are often a limited resource that multiple species use. There is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. While the answer to this question has important conservation implications, little experimental work has been done to examine it. Here, we aimed to experimentally test whether alien cavity nesting birds affect the occupancy of cavities and the resulting breeding success of native cavity breeders in a large urban park located in Tel Aviv, Israel. Over three breeding seasons, we manipulated the entry size of nest boxes and compared the occupancy and breeding success of birds in nest boxes of two treatments. These included nest boxes with large-entrance and small-entrance holes. The large-entrance holes allowed access for both the native and invasive birds (the two main aliens in the park are the common mynas and rose-ringed parakeets). The smaller-entrance boxes, on the other hand, allowed only the smaller sized native cavity breeders (great tits and house sparrows) to enter the boxes but prevented the alien species from entering. We found that the large-entrance nest boxes were occupied by five different bird species, comprising three natives (great tit, house sparrow, Scops owl) and two invasive species (common myna, rose-ringed parakeet) while the small-entrance boxes were only occupied by the two native species. The alien common mynas and rose-ringed parakeets occupied 77.5% of the large-entrance nest boxes whereas native species, mainly great tits, occupied less than 9% of the large-entrance boxes and 36.5% of the small-entrance boxes. When examining the occupancy of those cavities that were not occupied by the aliens, natives occupied both the small and large-entrance nest boxes equally. Three quarters (78%) of the great tits breeding in the large-entrance boxes were usurped by common mynas during the breeding season and as a result breeding success was

  5. Effects of Nest Spacing on Nest Occupation, Mating Success and Mating Behaviour in the Two-spotted Goby (Gobiusculus flavescens)

    OpenAIRE

    2011-01-01

    I investigated hoe different spacing of breeding sited affects different aspects of mating behaviour in the two-spotted goby. I found that clumped nest spacing affects nest occupations and reproductive success negatively. Clumped nest spacing incresed male agonistic behaviour and led to a higher variance in reproductive success.

  6. EFL Students' and Teachers' Attitudes toward Foreign Language Speaking Anxiety: A Look at NESTs and Non-NESTs

    Science.gov (United States)

    Han, Turgay; Tanriöver, Ahmet Serkan; Sahan, Özgür

    2016-01-01

    Native English Speaking Teachers (NESTs) have been employed in various English language teaching (ELT) positions and departments at private and state universities in Turkey, particularly over the last three decades. However, undergraduate EFL students' attitudes toward NESTs and Non-Native English Speaking Teachers (Non-NESTs) remain seriously…

  7. Advanced fluidic handling and use of two-phase flow for high throughput structural investigation of proteins on a microfluidic sample preparation platform

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Snakenborg, Detlef; Møller, M.

    2010-01-01

    Research on the structure of proteins can bring forth a wealth of information about biological function and can be used to better understand the processes in living cells. This paper reports a new microfluidic sample preparation system for the structural investigation of proteins by Small Angle X......-ray Scattering (SAXS). The system includes hardware and software features for precise fluidic control, synchrotron beamline control, UV absorbance measurements and automated data analysis. The precise fluidic handling capabilities are used to transport and precisely position samples as small as 500 n...

  8. Fluidic patch antenna based on liquid metal alloy/single-wall carbon-nanotubes operating at the S-band frequency

    Science.gov (United States)

    Aïssa, B.; Nedil, M.; Habib, M. A.; Haddad, E.; Jamroz, W.; Therriault, D.; Coulibaly, Y.; Rosei, F.

    2013-08-01

    This letter describes the fabrication and characterization of a fluidic patch antenna operating at the S-band frequency (4 GHz). The antenna prototype is composed of a nanocomposite material made by a liquid metal alloy (eutectic gallium indium) blended with single-wall carbon-nanotube (SWNTs). The nanocomposite is then enclosed in a polymeric substrate by employing the UV-assisted direct-writing technology. The fluidic antennas specimens feature excellent performances, in perfect agreement with simulations, showing an increase in the electrical conductivity and reflection coefficient with respect to the SWNTs concentration. The effect of the SWNTs on the long-term stability of antenna's mechanical properties is also demonstrated.

  9. Ant colonies prefer infected over uninfected nest sites

    DEFF Research Database (Denmark)

    Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley;

    2014-01-01

    During colony relocation, the selection of a new nest involves exploration and assessment of potential sites followed by colony movement on the basis of a collective decision making process. Hygiene and pathogen load of the potential nest sites are factors worker scouts might evaluate, given...... and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown...

  10. Estimating raptor nesting success: old and new approaches

    Science.gov (United States)

    Brown, Jessi L.; Steenhof, Karen; Kochert, Michael N.; Bond, Laura

    2013-01-01

    Studies of nesting success can be valuable in assessing the status of raptor populations, but differing monitoring protocols can present unique challenges when comparing populations of different species across time or geographic areas. We used large datasets from long-term studies of 3 raptor species to compare estimates of apparent nest success (ANS, the ratio of successful to total number of nesting attempts), Mayfield nesting success, and the logistic-exposure model of nest survival. Golden eagles (Aquila chrysaetos), prairie falcons (Falco mexicanus), and American kestrels (F. sparverius) differ in their breeding biology and the methods often used to monitor their reproduction. Mayfield and logistic-exposure models generated similar estimates of nesting success with similar levels of precision. Apparent nest success overestimated nesting success and was particularly sensitive to inclusion of nesting attempts discovered late in the nesting season. Thus, the ANS estimator is inappropriate when exact point estimates are required, especially when most raptor pairs cannot be located before or soon after laying eggs. However, ANS may be sufficient to assess long-term trends of species in which nesting attempts are highly detectable.

  11. Resource redistribution in polydomous ant nest networks: local or global?

    Science.gov (United States)

    Franks, Daniel W.; Robinson, Elva J.H.

    2014-01-01

    An important problem facing organisms in a heterogeneous environment is how to redistribute resources to where they are required. This is particularly complex in social insect societies as resources have to be moved both from the environment into the nest and between individuals within the nest. Polydomous ant colonies are split between multiple spatially separated, but socially connected, nests. Whether, and how, resources are redistributed between nests in polydomous colonies is unknown. We analyzed the nest networks of the facultatively polydomous wood ant Formica lugubris. Our results indicate that resource redistribution in polydomous F. lugubris colonies is organized at the local level between neighboring nests and not at the colony level. We found that internest trails connecting nests that differed more in their amount of foraging were stronger than trails between nests with more equal foraging activity. This indicates that resources are being exchanged directly from nests with a foraging excess to nests that require resources. In contrast, we found no significant relationships between nest properties, such as size and amount of foraging, and network measures such as centrality and connectedness. This indicates an absence of a colony-level resource exchange. This is a clear example of a complex behavior emerging as a result of local interactions between parts of a system. PMID:25214755

  12. Desmoplastic nested spindle cell tumours and nested stromal epithelial tumours of the liver.

    Science.gov (United States)

    Misra, Sunayana; Bihari, Chhagan

    2016-04-01

    Desmoplastic nested spindle cell tumour of liver (DNSTL), nested stromal-epithelial tumour (NSET) and calcifying nested stromal-epithelial tumour (CNSET) are recently described entities with similar morphology, immunohistochemistry and molecular genetics. These are rare entities with only three large case series described till date. These tumours commonly present in the paediatric age group. NSETs, in addition have been described to be associated with ectopic adrenocorticotropic hormone (ACTH) production and Cushingoid features. It is important to discuss this rare group of tumours with a low malignant potential as the most common radiological differential diagnosis is hepatoblastoma, which has a relatively poorer prognosis. Thus, a pathologist needs to keep this entity in mind, so as to offer a correct histological diagnosis.

  13. Grassland birds orient nests relative to nearby vegetation

    Science.gov (United States)

    Hoekman, S.T.; Ball, I.J.; Fondell, T.E.

    2002-01-01

    We studied orientation of nest sites relative to nearby vegetation for dabbling ducks (Cinnamon Teal, Anas cyanoptera; Blue-winged Teal, A. discors; Gadwall, A. strepera; Mallard, A. platyrhynchos; and Northern Shoveler, A. clypeata) and Short-eared Owls (Asio flammeus) in ungrazed grassland habitat during 1995-1997 in westcentral Montana. We estimated an index of vegetation height and density in intercardinal directions (NE, SE, SW, NW) immediately around nests. All species oriented nests with the least vegetation to the southeast and the most vegetation to either the southwest or northwest. Furthermore, maximum vegetation around nests shifted from the southwest to the northwest with increasing nest initiation date, apparently as a response of individuals tracking seasonal change in the afternoon solar path. Thus, nests were relatively exposed to solar insolation during cool morning hours but were shaded from intense insolation in the afternoon throughout the breeding season. We suggest that nest microhabitat was selected in part to moderate the thermal environment.

  14. Miniaturized total analysis systems: integration of electronics and fluidics using low-temperature co-fired ceramics.

    Science.gov (United States)

    Martínez-Cisneros, Cynthia S; Ibáñez-García, Núria; Valdés, Francisco; Alonso, Julián

    2007-11-01

    The advantages of microanalyzers, usually fabricated in silicon, glass, or polymers, are well-known. The design and construction of fluidic platforms are well-developed areas due to the perfectly established microfabrication technologies used. However, there is still the need to achieve devices that include not only the fluid management system but also the measurement electronics, so that real portable miniaturized analyzers can be obtained. Low-temperature co-fired ceramics technology permits the incorporation of actuators, such as micropumps and microvalves, controlled either magnetically, piezoelectrically, or thermally. Furthermore, electronic circuits can be also easily built exploiting the properties of these ceramics and the fact that they can be fabricated using a multilayer approach. In this work, taking advantage of the possibility of combining fluidics and electronics in a single substrate and using the same fabrication methodology, a chemical microanalyzer that integrates microfluidics, the detection system, and also the data acquisition and digital signal processing electronics is presented. To demonstrate the versatility of the technology, two alternative setups have been developed. In the first one, a modular configuration is proposed. In this case, the same electronic module can be used to determine different chemical parameters by simply exchanging the chemical module. In the second one, the monolithic integration of all the elements was accomplished, allowing the construction of compact and dedicated devices. Chloride ion microanalyzers have been constructed to demonstrate the operability of both device configurations. In all cases, the results obtained showed adequate analytical features.

  15. Logic digital fluidic in miniaturized functional devices: Perspective to the next generation of microfluidic lab-on-chips.

    Science.gov (United States)

    Zhang, Qiongdi; Zhang, Ming; Djeghlaf, Lyas; Bataille, Jeanne; Gamby, Jean; Haghiri-Gosnet, Anne-Marie; Pallandre, Antoine

    2017-04-01

    Microfluidics has emerged following the quest for scale reduction inherent to micro- and nanotechnologies. By definition, microfluidics manipulates fluids in small channels with dimensions of tens to hundreds of micrometers. Recently, microfluidics has been greatly developed and its influence extends not only the domains of chemical synthesis, bioanalysis, and medical researches but also optics and information technology. In this review article, we will shortly discuss an enlightening analogy between electrons transport in electronics and fluids transport in microfluidic channels. This analogy helps to master transport and sorting. We will present some complex microfluidic devices showing that the analogy is going a long way off toward more complex components with impressive similarities between electronics and microfluidics. We will in particular explore the vast manifold of fluidic operations with passive and active fluidic components, respectively, as well as the associated mechanisms and corresponding applications. Finally, some relevant applications and an outlook will be cited and presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Blackbeard Island National Wildlife Refuge Loggerhead Sea Turtle Nest Monitoring: End of Season Report - 2013

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The 2013 Loggerhead sea turtle nesting season resulted in 284 nests with 17,915 emerged hatchlings. Of the 284 nests, 162 (57%) remained in situ with 122 (43%) nests...

  17. Nest-site selection and nest success of an Arctic-breeding passerine, Smith's Longspur, in a changing climate

    Science.gov (United States)

    McFarland, Heather R.; Kendall, Steve J.; Powell, Abby

    2017-01-01

    Despite changes in shrub cover and weather patterns associated with climate change in the Arctic, little is known about the breeding requirements of most passerines tied to northern regions. We investigated the nesting biology and nest habitat characteristics of Smith's Longspurs (Calcarius pictus) in 2 study areas in the Brooks Range of Alaska, USA. First, we examined variation in nesting phenology in relation to local temperatures. We then characterized nesting habitat and analyzed nest-site selection for a subset of nests (n = 86) in comparison with paired random points. Finally, we estimated the daily survival rate of 257 nests found in 2007–2013 with respect to both habitat characteristics and weather variables. Nest initiation was delayed in years with snow events, heavy rain, and freezing temperatures early in the breeding season. Nests were typically found in open, low-shrub tundra, and never among tall shrubs (mean shrub height at nests = 26.8 ± 6.7 cm). We observed weak nest-site selection patterns. Considering the similarity between nest sites and paired random points, coupled with the unique social mating system of Smith's Longspurs, we suggest that habitat selection may occur at the neighborhood scale and not at the nest-site scale. The best approximating model explaining nest survival suggested a positive relationship with the numbers of days above 21°C that an individual nest experienced; there was little support for models containing habitat variables. The daily nest survival rate was high (0.972–0.982) compared with that of most passerines in forested or grassland habitats, but similar to that of passerines nesting on tundra. Considering their high nesting success and ability to delay nest initiation during inclement weather, Smith's Longspurs may be resilient to predicted changes in weather regimes on the breeding grounds. Thus, the greatest threat to breeding Smith's Longspurs associated with climate change may be the loss of low

  18. Island characteristics within wetlands influence waterbird nest success and abundance

    Science.gov (United States)

    Hartman, Christopher; Ackerman, Josh; Herzog, Mark

    2016-01-01

    Coastal waterbird populations are threatened by habitat loss and degradation from urban and agricultural development and forecasted sea level rise associated with climate change. Remaining wetlands often must be managed to ensure that waterbird habitat needs, and other ecosystem functions, are met. For many waterbirds, the availability of island nesting habitat is important for conserving breeding populations. We used linear mixed models to investigate the influence of pond and island landscape characteristics on nest abundance and nest success of American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Forster's terns (Sterna forsteri) in San Francisco Bay, California, USA, based on a 9-year dataset that included >9,000 nests. Nest abundance and nest success were greatest within ponds and on individual islands located either 4 km from San Francisco Bay. Further, nest abundance was greater within ponds with relatively few islands, and on linear-shaped, highly elongated islands compared to more rounded islands. Nest success was greater on islands located away from the nearest surrounding pond levee. Compared to more rounded islands, linear islands contained more near-water habitat preferred by many nesting waterbirds. Islands located away from pond levees may provide greater protection from terrestrial egg and chick predators. Our results indicate that creating and maintaining a few, relatively small, highly elongated and narrow islands away from mainland levees, in as many wetland ponds as possible would be effective at providing waterbirds with preferred nesting habitat.

  19. Does cooperation mean kinship between spatially discrete ant nests?

    Science.gov (United States)

    Procter, Duncan S; Cottrell, Joan E; Watts, Kevin; A'Hara, Stuart W; Hofreiter, Michael; Robinson, Elva J H

    2016-12-01

    Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.

  20. Experimental nest site limitation affects reproductive strategies and parental investment in a hole-nesting passerine

    NARCIS (Netherlands)

    Jacot, A.; Valcu, M.; Van Oers, K.; Kempenaers, B.

    2009-01-01

    In resource defence mating systems, males monopolize a resource that is of primary importance for breeding females. For secondary cavity nesters, the availability of suitable nesting sites is important in determining the strength of intrasexual competition, whereby phenotypic and behavioural traits

  1. Rapid Multiplexed Flow Cytometric Assay for Botulinum Neurotoxin Detection Using an Automated Fluidic Microbead-Trapping Flow Cell for Enhanced Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ozanich, Richard M.; Bruckner-Lea, Cindy J.; Warner, Marvin G.; Miller, Keith D.; Antolick, Kathryn C.; Marks, James D.; Lou, Jianlong; Grate, Jay W.

    2009-07-15

    A bead-based sandwich immunoassay for botulinum neurotoxin serotype A (BoNT/A) has been developed and demonstrated using a recombinant 50 kDa fragment (BoNT/A-HC-fragment) of the BoNT/A heavy chain (BoNT/A-HC) as a structurally valid simulant. Three different anti-BoNT/A antibodies were attached to three different fluorescent dye encoded flow cytometry beads for multiplexing. The assay was conducted in two formats: a manual microcentrifuge tube format and an automated fluidic system format. Flow cytometry detection was used for both formats. The fluidic system used a novel microbead-trapping flow cell to capture antibody-coupled beads with subsequent sequential perfusion of sample, wash, dye-labeled reporter antibody, and final wash solutions. After the reaction period, the beads were collected for analysis by flow cytometry. Sandwich assays performed on the fluidic system gave median fluorescence intensity signals on the flow cytometer that were 2-4 times higher than assays performed manually in the same amount of time. Limits of detection were estimated at 1 pM (~50 pg/mL for BoNT/A-HC-fragment) for the 15 minute fluidic assay.

  2. Flexibility in nest-site choice and nesting success of Turdus rufiventris (Turdidae) in a montane forest in northwestern argentina

    Science.gov (United States)

    Lomascolo, S.B.; Monmany, A.C.; Malizia, A.; Martin, T.E.

    2010-01-01

    We studied the consequences of nest-site choice on nesting success under differing disturbance levels for the Rufous-bellied Thrush (Turdus rufiventris). We compared nest-site choice and nest success between a disturbed site and an undisturbed site in a montane subtropical forest in northwestern Argentina. We found no overall difference in daily predation rate (DPR) between the disturbed and undisturbed sites. However, DPR of nests on bromeliads was significantly lower at the microhabitat level than on other types of subtrates at the disturbed site. T. rufiventris used bromeliads for nesting more often than expected by chance at the disturbed site. DPR did not differ between substrates at the undisturbed site and T. rufiventris used all substrates according to their availability. Nests had higher predation at the disturbed site when DPR on non-bromeliad substrates was compared between disturbed and undisturbed sites. Nest fate was independent of nest height. Our results suggest T. rufiventris' flexibility in nest-site choice, as reflected by increased use of the safest sites, i.e., bromeliads, in the disturbed site compared to the undisturbed site, may allow this species to survive in an otherwise much riskier habitat. Our results illustrate how microhabitat-scale effects can mediate landscape scale effects. ?? 2010 by the Wilson Ornithological Society.

  3. Nests with numerous SOX10 and MiTF-positive cells in lichenoid inflammation: pseudomelanocytic nests or authentic melanocytic proliferation?

    Science.gov (United States)

    Silva, Claudine Yap; Goldberg, Lynne J; Mahalingam, Meera; Bhawan, Jag; Wolpowitz, Deon

    2011-10-01

    Pseudomelanocytic nests in the setting of lichenoid inflammation can mimic atypical melanocytic proliferations. Both melanocytic and cytokeratin immunohistochemical stains may be utilized to differentiate these entities. Unlike true melanocytic nests, pseudomelanocytic nests contain Melanoma Antigen Recognized by T-cells 1 (MART-1)/ Melan-A-positive cells and cells positive for pan-cytokeratins, CD3 and/or CD68. Recently, rare (1-2 cells/nest) microphthalmia- associated transcription factor (MiTF)-positive cells were also reported in pseudomelanocytic nests. We present a 48-year-old man with a 2 × 3 cm violaceous to hyperpigmented, non-blanching, polygonal patch on the neck. Histopathology showed focal epidermal atrophy, irregularly distributed junctional nests and a lichenoid infiltrate with colloid bodies. Immunoperoxidase studies revealed occasional pan-cytokeratin and MART-1/Melan-A-positive staining in nests as well as focal S-100 protein-positive cells. Importantly, the majority of nests showed numerous cells positive for MiTF and SOX10 (>2 cells/nest and some the majority of cells). This combined staining pattern confounds the above-described immunohistochemical distinction between pseudo and true melanocytic nests. Clinically felt to represent unilateral lichen planus pigmentosus/erythema dyschromicum perstans and not malignant melanoma in situ, this lesion highlights the importance of clinicopathologic correlation and suggests either a new melanocytic entity or a novel pattern of benign melanocytic reorganization in a subset of lichenoid dermatitides.

  4. Generation of arbitrary monotonic concentration profiles by a serial dilution microfluidic network composed of microchannels with a high fluidic-resistance ratio.

    Science.gov (United States)

    Hattori, Koji; Sugiura, Shinji; Kanamori, Toshiyuki

    2009-06-21

    This paper reports a serial dilution microfluidic network composed of microchannels with a high fluidic-resistance ratio for generating linear concentration profiles as well as logarithmic concentration profiles spanning 3 and 6 orders of magnitude. The microfluidic networks were composed of thin fluidic-resistance microchannels with 160 to 730 microm(2) cross-sectional areas and thick diffusion-mixing microchannels with 3,600 to 17,000 microm(2) cross-sectional areas, and were fabricated from polydimethylsiloxane by multilayer photolithography and replica molding. We proposed a design algorithm of the microfluidic network for an arbitrary monotonic concentration profile by means of a hydrodynamic calculation. Because of the high fluidic-resistance ratio of the fluidic-resistance microchannels to the diffusion-mixing microchannels, appropriate geometry and dimensions of the fluidic-resistance microchannels allowed us to obtain desired concentration profiles. The fabricated microfluidic network was compact, occupying a 8 x 18 to 21.0 x 13.5 mm(2) area on the microchip. Both the linear and the logarithmic concentration profiles were successfully generated with the error less than 15% for the linear concentration profile, 22% and 35% for the logarithmic concentration profiles of 3 and 6 orders of magnitude, respectively. The generated linear concentration profiles of the small molecule, calcein, were independent of the flow rate within the range of 0.009 to 0.23 microL/min. The concentration profiles of the large molecules, dextrans, depended on the flow rate and molecular weight. The required residence time of large molecules in the diffusion-mixing microchannel was correlated with dimensionless diffusion time, Fick number, and was discussed based on the scaling law. These compact, stable serial dilution microfluidic networks are expected to be applied to various integrated on-chip analyses.

  5. Characteristic Formulae for Relations with Nested Fixed Points

    Directory of Open Access Journals (Sweden)

    Luca Aceto

    2012-02-01

    Full Text Available A general framework for the connection between characteristic formulae and behavioral semantics is described in [2]. This approach does not suitably cover semantics defined by nested fixed points, such as the n-nested simulation semantics for n greater than 2. In this study we address this deficiency and give a description of nested fixed points that extends the approach for single fixed points in an intuitive and comprehensive way.

  6. Sandhill crane abundance and nesting ecology at Grays Lake, Idaho

    Science.gov (United States)

    Austin, J.E.; Henry, A.R.; Ball, I.J.

    2007-01-01

    We examined population size and factors influencing nest survival of greater sandhill cranes (Grus canadensis tabida) at Grays Lake National Wildlife Refuge, Idaho, USA, during 1997-2000. Average local population of cranes from late April to early May, 1998-2000, was 735 cranes, 34% higher than that reported for May 1970-1971. We estimated 228 (SE = 30) nests in the basin core (excluding renests), 14% higher than a 1971 estimate. Apparent nest success in our study (x?? = 60%, n = 519 nests) was lower than reported for Grays Lake 30-50 years earlier. Daily survival rates (DSRs) of all nests averaged 0.9707 (41.2%). The best model explaining nest survival included year and water depth and their interaction. Nest survival was highest (DSR = 0.9827) in 1998 compared with other years (0.9698-0.9707). Nest survival changed little relative to water depth in 1998, when flooding was extensive and alternative prey (microtines) irrupted, but declined markedly with lower water levels in 2000, the driest year studied. Hypotheses relating nest survival to vegetation height, land use (idle, summer grazing, fall grazing), and date were not supported. In a before-after-control-impact design using 12 experimental fields, nest survival differed among years but not among management treatments (idle, fall graze, fall burn, and summer-graze-idle rotation), nor was there an interaction between year and treatments. However, DSRs in fall-burn fields declined from 0.9781 in 1997-1998 to 0.9503 in 1999-2000 (posttreatment). Changes in the predator community have likely contributed to declines in nest success since the 1950s and 1970s. Our results did not support earlier concerns about effects of habitat management practices on crane productivity. Nest survival could best be enhanced by managing spring water levels. Managers should continue censuses during late April to evaluate long-term relationships to habitat conditions and management.

  7. Nesting ecology of waterbirds at Grays Lake, Idaho

    Science.gov (United States)

    Austin, J.E.; Pyle, W.H.

    2004-01-01

    Montane wetlands provide valuable habitat for nesting waterfowl and other waterbirds in the western United States, but relatively little information is available about the nesting ecology of their waterbird communities. We describe the general nesting ecology of breeding waterbirds at a large, shallow montane wetland in southeast Idaho during 1997-2000. Habitats included upland grasslands and intermittently to semipermanently flooded wetland habitats. We located a total of 1207 nests of 23 bird species: eared grebe (Podiceps nigricollis), Canada goose (Branta canadensis), mallard (Anas platyrhynchos), gadwall (A. strepera), American wigeon (A. americana), green-winged teal (A. crecca), blue-winged teal (A. discors), cinnamon teal (A. cyanoptera), northern shoveler (A. clypeata), northern pintail (A. acuta), redhead (Aythya americana), canvasback (A. valisineria), lesser scaup (A. affinis), ruddy duck (Oxyuris jamaicensis), northern harrier (Circus cyaneus), American coot (Fulica americana), Virginia rail (Rallus limicola), greater sandhill crane (Grus canadensis tabida), American avocet (Recurvirostra americana), long-billed curlew (Numenius americanus), Wilsons snipe (Gallinago delicta), Wilsons phalarope (Phalaropus tricolor), and short-eared owl (Asio flammeus). Most nests were initiated in May-early June and were terminated (hatched or destroyed) by the third week of June. Mean daily survival rate (DSR) for Canada goose nests was 0.954 0.005 (SE) (n = 127 nests), equivalent to Mayfield nest success of 21%. Mean DSR for dabbling duck nests over all four years was 0.938 0.006 (n = 141), equivalent to Mayfield nest success of 11%. For all other species where we found >10 nests each year (eared grebe, redhead, canvasback, coot, sandhill crane, American avocet, and Wilsons snipe), >50% of nests found hatched at least one young. Success rates for geese, cranes, and ducks were lower than reported for Grays Lake during 1949-1951 and lower than most other wetlands in

  8. Generalized Derivations and Bilocal Jordan Derivations of Nest Algebras

    Directory of Open Access Journals (Sweden)

    Dangui Yan

    2011-01-01

    Full Text Available Let H be a complex Hilbert space and B(H the collection of all linear bounded operators, A is the closed subspace lattice including 0 an H, then A is a nest, accordingly alg A={T∈B(H:TN⊆N,  ∀N∈A} is a nest algebra. It will be shown that of nest algebra, generalized derivations are generalized inner derivations, and bilocal Jordan derivations are inner derivations.

  9. Duck nesting in intensively farmed areas of North Dakota

    Science.gov (United States)

    Higgins, K.F.

    1977-01-01

    A study to determine the major factors limiting duck nesting and production on intensively farmed areas in eastern North Dakota was conducted from 1969 through 1974. A total of 186 duck nests was found during searches on 6,018 ha of upland. Nest density per km2 for 5 major habitat types was 20.2 in untilled upland, 3.7 in standing grain stubble, 1.6 in mulched grain stubble, 1.2 in summer fallow, and 1.1 in growing grain. Pintails (Anas acuta) nested in cultivated cropland types in greater prevalence than other duck species. Nest densities were 12 times greater on untilled upland (20.2/km2) than on annually tilled cropland (1.7/km2), and hatched-clutch densities were 16 times greater on untilled upland (4.8/km2) than on annually tilled cropland (0.3/km2). Hatching success was greater on untilled upland (25%) than on tilled cropland (17%). Of 186 nests found, 77 percent did not hatch; 76 percent of the failures were attributed to predators and 19 percent to farming operations. Poor quality nesting cover, the result of intensive land use practices, and nesting failures caused by machinery and predators mainly mammals, were the principal factors limiting duck nesting and production on intensively farmed areas.

  10. Nest success of grassland sparrows on reclaimed surface mines

    Science.gov (United States)

    Stauffer, G.E.; Diefenbach, D.R.; Marshall, M.R.; Brauning, D.W.

    2011-01-01

    Grasslands resulting from surface mine reclamation support grassland songbird populations in several midwestern and eastern states in the United States, especially where reclaimed mines are large (>1,000ha). However, most reclaimed surface mines in Pennsylvania are small (success is unknown. We evaluated nest success of grasshopper (Ammodramus savannarum), Henslow's (A. henslowii), and Savannah sparrows (Passerculus sandwichensis) on 4 reclaimed surface mines (50-180ha) in western Pennsylvania, USA from 2006 to 2007. Overall nest success based on mean covariate values was 0.435 (95% CI = 0.376-0.504) for grasshopper sparrows, 0.396 (95% CI = 0.295-0.533) for Henslow's sparrows, and 0.158 (95% CI = 0.063-0.392) for Savannah sparrows. These estimates of nest success are comparable to those on larger reclaimed mines and other habitats. Grasshopper and Henslow's sparrow nests that were well concealed were less likely to fail than highly visible nests (??visible = -0.028, CI = -0.051 to -0.005 for grasshopper sparrows; ??visible = -0.063, CI = -0.112 to -0.014 for Henslow's sparrows), and nests in areas with surrounding deep litter were more likely to fail than nests in areas with shallow litter (??litterD = -0.145, CI = -0.335 to 0.045 for grasshopper sparrows; ??litterD = -0.676, CI = -1.187 to -0.116 for Henslow's sparrows). Savannah sparrow nests in areas with high visual obstruction by vegetation were less likely to fail than nests in areas with sparse and short vegetation (??VisOb = 0.048, CI = 0.006-0.091). Daily probability of survival for grasshopper sparrow nests was greatest early and late in the breeding season, and Savannah sparrow nest survival followed a decreasing linear trend. Nest survival of Henslow's sparrows was greater on warm days (??temp = 0.197, CI = 0.014-0.379), whereas for Savannah sparrows nest survival decreased on warm days and on days with rain, but for Savannah sparrows confidence intervals of weather effects included zero (??temp = -0

  11. Edible bird's nest: food or medicine?

    Science.gov (United States)

    Wong, Rebecca S Y

    2013-09-01

    Edible bird's nest (EBN) is derived from the saliva of certain types of swiftlets. It is consumed in many parts of the world for its nutritional and medicinal values. Although many claims have been made on the therapeutic and health-promoting effects of EBN, scientific documentations regarding these effects are very limited in published literature. It is not until recently that the biological effects of EBN are being investigated and evidence-based studies are being conducted. Several studies have found that EBN may enhance cell proliferation and differentiation and various beneficial effects have been reported in vitro as well as in vivo. While these studies point towards the potential use of EBN in the treatment or even prevention of several diseases, the mechanisms of action of EBN remain largely unknown and more explorations are needed. This review is one of the very few scientific reviews on EBN which focuses on recent evidence-based discoveries.

  12. Development of the nested fiber filter

    Science.gov (United States)

    Litt, R. D.; Conkle, H. N.; Raghavan, J. K.

    Battelle has tested the Nested Fiber Filter (NFF) as a particulate control device for high temperature, high-pressure (HTHP) applications. Battelle funded initial bench-scale tests which were the basis for patents and a concept applying the NFF. Subsequent parametric tests in a 6-inch diameter reactor established excellent particulate capture performance, greater than 99 percent, for conditions up to 1600 F and 6 atmospheres. Effective cleaning/regeneration of the NFF was achieved in the 6-inch scale with acoustic and mechanical vibration. A pulse combustor was tested in an integrated NFF arrangement because of compatibility with the HTBP conditions. This arrangement provided the basis for larger scale tests under the subject contract. A 6-sq ft test module was designed and installed with an existing fluidized bed combustor for additional development and testing.

  13. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM

    Directory of Open Access Journals (Sweden)

    Ladeesh V. G.

    2017-01-01

    Full Text Available Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of machining parameters on surface roughness. Voltage, duty factor, frequency and tool feed rate are identified as the significant factors for controlling surface roughness of the channels produced by G-ECDM. A mathematical model was developed for surface roughness by considering the grinding action and thermal effects of electrochemical discharges in material removal. Experiments are conducted to validate the model and the results obtained are in good agreement with that predicted by the model.

  14. A bladder-free, non-fluidic, conductive McKibben artificial muscle operated electro-thermally

    Science.gov (United States)

    Sangian, Danial; Foroughi, Javad; Farajikhah, Syamak; Naficy, Sina; Spinks, Geoffrey M.

    2017-01-01

    Fluidic McKibben artificial muscles that operate pneumatically or hydraulically provide excellent performance, but require bulky pumps/compressors, valves and connecting lines. Use of a pressure generating material, such as thermally expanding paraffin wax, can eliminate the need for these pumps and associated infrastructure. Here we further develop this concept by introducing the first bladderless McKibben muscle wherein molten paraffin is contained by surface tension within a tailored braid. Incorporation of electrically conductive wires in the braid allows for convenient Joule heating of the paraffin. The muscle is light (0.14 g) with a diameter of 1.4 mm and is capable of generating a tensile stress of 50 kPa (0.039 N) in 20 s. The maximum contraction strain of 10% (7.6 kPa given load) was achieved in 60 s with an applied electrical power of 0.35 W.

  15. A High-Voltage Integrated Circuit Engine for a Dielectrophoresis-based Programmable Micro-Fluidic Processor

    Science.gov (United States)

    Current, K. Wayne; Yuk, Kelvin; McConaghy, Charles; Gascoyne, Peter R. C.; Schwartz, Jon A.; Vykoukal, Jody V.; Andrews, Craig

    2010-01-01

    A high-voltage (HV) integrated circuit has been demonstrated to transport droplets on programmable paths across its coated surface. This chip is the engine for a dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip system. This chip creates DEP forces that move and help inject droplets. Electrode excitation voltage and frequency are variable. With the electrodes driven with a 100V peak-to-peak periodic waveform, the maximum high-voltage electrode waveform frequency is about 200Hz. Data communication rate is variable up to 250kHz. This demonstration chip has a 32×32 array of nominally 100V electrode drivers. It is fabricated in a 130V SOI CMOS fabrication technology, dissipates a maximum of 1.87W, and is about 10.4 mm × 8.2 mm. PMID:23989241

  16. Lab-on-a-brain: Implantable micro-optical fluidic devices for neural cell analysis in vivo

    Science.gov (United States)

    Takehara, Hiroaki; Nagaoka, Akira; Noguchi, Jun; Akagi, Takanori; Kasai, Haruo; Ichiki, Takanori

    2014-10-01

    The high-resolution imaging of neural cells in vivo has brought about great progress in neuroscience research. Here, we report a novel experimental platform, where the intact brain of a living mouse can be studied with the aid of a surgically implanted micro-optical fluidic device; acting as an interface between neurons and the outer world. The newly developed device provides the functions required for the long-term and high-resolution observation of the fine structures of neurons by two-photon laser scanning microscopy and the microfluidic delivery of chemicals or drugs directly into the brain. A proof-of-concept experiment of single-synapse stimulation by two-photon uncaging of caged glutamate and observation of dendritic spine shrinkage over subsequent days demonstrated a promising use for the present technology.

  17. A constrained particle dynamics for continuum-particle hybrid method in micro-and nano-fluidics

    Institute of Scientific and Technical Information of China (English)

    Jia Cui; GuoWei He; Dewei Qi

    2006-01-01

    A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics,where fluids are described by a molecular dynamics (MD) in one domain and by the Navier-Stokes (NS) equations in another domain.In order to ensure the continuity of momentum flux,the continuum and molecular dynamics in the overlap domain are coupled through a constrained particle dynamics.The constrained particle dynamics is constructed with a virtual damping force and a virtual added mass force.The sudden-start Couette flows with either non-Slip or slip boundary condition are used to test the hybrid method.It is shown that the results obtained are quantitatively in agreement with the analytical solutions under the non-slip boundary conditions and the full MD simulations under the slip boundary conditions.

  18. Fast, label-free tracking of single viruses and weakly scattering nanoparticles in a nano-fluidic optical fiber

    CERN Document Server

    Faez, Sanli; Weidlich, Stefan; Garmann, Rees F; Wondraczek, Katrin; Zeisberger, Matthias; Schmidt, Markus A; Orrit, Michel; Manoharan, Vinothan N

    2015-01-01

    High-speed tracking of single particles is a gateway to understanding physical, chemical, and biological processes at the nanoscale. It is also a major experimental challenge, particularly for small, nanometer-scale particles. Although methods such as confocal or fluorescence microscopy offer both high spatial resolution and high signal-to-background ratios, the fluorescence emission lifetime limits the measurement speed, while photobleaching and thermal diffusion limit the duration of measurements. Here we present a tracking method based on elastic light scattering that enables long-duration measurements of nanoparticle dynamics at rates of thousands of frames per second. We contain the particles within a single-mode silica fiber containing a sub-wavelength, nano-fluidic channel and illuminate them using the fiber's strongly confined optical mode. The diffusing particles in this cylinderical geometry are continuously illuminated inside the collection focal plane. We show that the method can track unlabeled d...

  19. Daily survival rate for nests and chicks of Least Terns (Sternula antillarum) at natural nest sites in South Carolina

    Science.gov (United States)

    Brooks, Gillian L.; Sanders, Felicia J.; Gerard, Patrick D.; Jodice, Patrick G.

    2013-01-01

    Although a species of conservation concern, little is known about the reproductive success of Least Terns (Sternula antillarum) throughout the southeastern USA where availability of natural beaches for nesting is limited. Daily survival rate (DSR) of nests and chicks was examined at four natural nesting sites in Cape Romain National Wildlife Refuge, South Carolina, 2009–2010. Measures of nest success (n = 257 nests) ranged from 0–93% among colony sites. The DSR of nests was primarily related to colony site, but year and estimates of predation risk also were related to DSR. Predation was the principal cause of identifiable nest loss, accounting for 47% of nest failures when the two years of data were pooled. The probability (± SE) of a chick surviving from hatching to fledging = 0.449 ± 0.01 (n = 92 chicks). DSR of chicks was negatively related to tide height and rainfall. Therefore, productivity of Least Terns is being lost during both the nesting and chick stage through a combination of biotic and abiotic factors that may prove difficult to fully mitigate or manage. Although natural nesting sites within Cape Romain National Wildlife Refuge intermittently produce successful nests, the consistency of productivity over the long term is still unknown. Given that the long term availability of anthropogenic nest sites (e.g., rooftops, dredge-spoil islands) for Least Terns is questionable, further research is required both locally and throughout the region to assess the extent to which natural sites act as population sources or sinks.

  20. The effect of nesting material on the nest-building and maternal behavior of domestic sows and piglet production.

    Science.gov (United States)

    Chaloupková, H; Illmann, G; Neuhauserová, K; Simecková, M; Kratinová, P

    2011-02-01

    Nest building is an important part of maternal behavior in domestic pigs. The aim of the study was to assess the effect of nesting material sawdust vs. straw on sow behavior 24 h before and after birth of the first piglet (BFP) and piglet production. Sows, housed in farrowing crates, were randomly divided into 2 treatments: sawdust (n = 12) and straw (n = 13). Sawdust and straw were provided during the pre- and parturient period; after parturition, straw was given to both experimental groups. The prepartum nesting period (the time interval between the first and last nest-building records, including all other activity and resting before BFP), the nesting records (number of nesting records), nesting duration (duration of all nesting records), the start and termination of nesting, and the frequency of prepartum postural changes were collected 24 h before BFP. After BFP, number of nesting records and time to first sucking of the litter were collected. Frequency of postural changes and duration of udder access were collected 24 h after BFP during 3 time periods (during parturition, from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP) and the frequency of nursing during 2 time periods (from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP). Piglet BW gain and mortality were estimated 24 h after BFP. Data were analyzed using PROC MIXED and the probability of the piglet mortality using PROC GENMOD in SAS. Nesting material did not affect (P > 0.10) most of sow prepartum nesting behavior and had no effect (P > 0.10) on the prepartum frequency of postural changes. Sows from the sawdust treatment had a longer nesting period (P 0.10) of the nesting material on piglet BW gain and mortality was found. The results suggest that sawdust compared with straw as nesting material provided to sows before and through parturition does not negatively affect maternal behavior during the 24 h before and after parturition or piglet production. Therefore

  1. Hatchling sex ratio, body weight and nest parameters for Chelonia mydas nesting on Sugözü beaches (Turkey

    Directory of Open Access Journals (Sweden)

    Kılıç, Ç.

    2014-12-01

    Full Text Available We investigated the relationship between nest parameters, hatchling body mass, and sex ratio of green turtle, Chelonia mydas, embryos and hatchlings at the temperate nesting rookery of Sugözü Beach (Adana–Turkey. Mean nest temperature and distance from the sea were correlated, while mean nest temperature and incubation period were inversely related. There was no apparent relationship between incubation period and hatchling mass. Hatchling and embryo sex ratios, determined by histological examination, showed a 70.5% and 93.5% female bias, respectively. There was no correlation between sex and body weight of hatchlings,

  2. A hierarchical nest survival model integrating incomplete temporally varying covariates

    Science.gov (United States)

    Converse, Sarah J.; Royle, J. Andrew; Adler, Peter H.; Urbanek, Richard P.; Barzan, Jeb A.

    2013-01-01

    Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

  3. Local individual preferences for nest materials in a passerine bird.

    Directory of Open Access Journals (Sweden)

    Adèle Mennerat

    Full Text Available BACKGROUND: Variation in the behavioural repertoire of animals is acquired by learning in a range of animal species. In nest-building birds, the assemblage of nest materials in an appropriate structure is often typical of a bird genus or species. Yet plasticity in the selection of nest materials may be beneficial because the nature and abundance of nest materials vary across habitats. Such plasticity can be learned, either individually or socially. In Corsican populations of blue tits Cyanistes caeruleus, females regularly add in their nests fragments of several species of aromatic plants during the whole breeding period. The selected plants represent a small fraction of the species present in the environment and have positive effects on nestlings. METHODOLOGY/PRINCIPAL FINDINGS: We investigated spatiotemporal variations of this behaviour to test whether the aromatic plant species composition in nests depends on 1 plant availability in territories, 2 female experience or 3 female identity. Our results indicate that territory plays a very marginal role in the aromatic plant species composition of nests. Female experience is not related to a change in nest plant composition. Actually, this composition clearly depends on female identity, i.e. results from individual preferences which, furthermore, are repeatable both within and across years. A puzzling fact is the strong difference in plant species composition of nests across distinct study plots. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that plant species composition of nests results from individual preferences that are homogeneous within study plots. We propose several hypotheses to interpret this pattern of spatial variation before discussing them in the light of preliminary results. As a conclusion, we cannot exclude the possibility of social transmission of individual preferences for aromatic plants. This is an exciting perspective for further work in birds, where nest construction

  4. Nest survival of forest birds in the Mississippi Alluvial Valley

    Science.gov (United States)

    Twedt, D.J.; Wilson, R.R.; Henne-Kerr, J.L.; Hamilton, R.B.

    2001-01-01

    In the Mississippi Alluvial Valley, flood control has led to a drastic reduction in the area of forest habitat and altered the patchwork of forest cover types. Silvicultural management of the remaining fragmented forests has changed to reflect the altered hydrology of the forests, current economic conditions of the area, and demand for forest products. Because forest type and silvicultural management impact forest birds, differences in avian productivity within these forests directly impact bird conservation. To assist in conservation planning, we evaluated daily nest survival, nest predation rates, and brood parasitism rates of forest birds in relation to different forest cover types and silvicultural management strategies within this floodplain. Within bottomland hardwood forests, nest success of blue-gray gnatcatcher (Polioptila caerulea, 13%), eastern towhee (Pipilo erythrophthalmus, 28%), indigo bunting (Passerina cyanea, 18%), northern cardinal (Cardinalis cardinalis, 22%), and yellow-billed cuckoo (Coccyzus americanus, 18%) did not differ from that within intensively managed cottonwood plantations. However, average daily survival of 542 open-cup nests of 19 bird species in bottomland hardwoods (0.9516 + 0.0028, -27% nest success) was greater than that of 543 nests of 18 species in cotlonwood plantations (0.9298 + 0.0035, -15% nest success). Differences in daily nest survival rates likely resulted from a combination of differences in the predator community--particularly fire ants (Solenopsis invicta)--and a marked difference in species composition of birds breeding within these 2 forest types. At least 39% of nests in bottomland hardwood forests and 65% of nests in cottonwood plantations were depredated. Rates of parasitism by brown-headed cowbirds (Molothrus ater) were greater in managed cottonwoods (24%) than in bottomland hardwoods (9%). Nest success in planted cottonwood plantations for 18 species combined (-14%), and for yellow-breasted chat (Icteria

  5. Factors affecting Culicoides species composition and abundance in avian nests.

    Science.gov (United States)

    Martínez-de la Puente, J; Merino, S; Tomás, G; Moreno, J; Morales, J; Lobato, E; Talavera, S; Sarto I Monteys, V

    2009-08-01

    Mechanisms affecting patterns of vector distribution among host individuals may influence the population and evolutionary dynamics of vectors, hosts and the parasites transmitted. We studied the role of different factors affecting the species composition and abundance of Culicoides found in nests of the blue tit (Cyanistes caeruleus). We identified 1531 females and 2 males of 7 different Culicoides species in nests, with C. simulator being the most abundant species, followed by C. kibunensis, C. festivipennis, C. segnis, C. truncorum, C. pictipennis and C. circumscriptus. We conducted a medicationxfumigation experiment randomly assigning bird's nests to different treatments, thereby generating groups of medicated and control pairs breeding in fumigated and control nests. Medicated pairs were injected with the anti-malarial drug Primaquine diluted in saline solution while control pairs were injected with saline solution. The fumigation treatment was carried out using insecticide solution or water for fumigated and control nests respectively. Brood size was the main factor associated with the abundance of biting midges probably because more nestlings may produce higher quantities of vector attractants. In addition, birds medicated against haemoparasites breeding in non-fumigated nests supported a higher abundance of C. festivipennis than the rest of the groups. Also, we found that the fumigation treatment reduced the abundance of engorged Culicoides in both medicated and control nests, thus indicating a reduction of feeding success produced by the insecticide. These results represent the first evidence for the role of different factors in affecting the Culicoides infracommunity in wild avian nests.

  6. Common loon nest defense against an American mink

    Science.gov (United States)

    McCarthy, Kyle P.; Destefano, Stephen

    2011-01-01

    We describe a successful nest defense strategy of an adult Gavia immer (Common Loon) during an attempted predation event by a Nevison vison (American Mink) at Umbagog National Wildlife Refuge, NH. It is suspected that mink occasionally depredate loon nests, but defense strategies have not been described previously.

  7. Preferences for nest boxes as environmental enrichment for laboratory mice

    NARCIS (Netherlands)

    Van de Weerd, HA; Van Loo, PLP; Van Zutphen, LFM; Koolhaas, JM; Baumans, [No Value

    1998-01-01

    In nature, mice live in burrows with nest chambers where they breed and may hide from predators. In the laboratory, a shelter or refuge is an easily applicable form of enrichment which may enhance the welfare of laboratory mice by giving them more control over their environment. Six nest boxes made

  8. Animating Nested Taylor Polynomials to Approximate a Function

    Science.gov (United States)

    Mazzone, Eric F.; Piper, Bruce R.

    2010-01-01

    The way that Taylor polynomials approximate functions can be demonstrated by moving the center point while keeping the degree fixed. These animations are particularly nice when the Taylor polynomials do not intersect and form a nested family. We prove a result that shows when this nesting occurs. The animations can be shown in class or…

  9. Brunn nests masquerading as bladder tumor: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Hee; Byun, Kyung Hwan; Jeon, Ji Min [College of Medicine, Pochon CHA University, Pochon (Korea, Republic of)

    2005-07-15

    Brunn nests are the most common proliferative lesions of the bladder uroepithelium, but exuberant proliferation can mimic bladder tumor on radiologic imaging and cystoscopy. We describe a case of pathologically proven Brunn nests in a 34-year-old man, misdiagnosed as bladder tumor on preoperative imaging studies.

  10. Nest ectoparasites increase physiological stress in breeding birds: an experiment

    Science.gov (United States)

    Martínez-de La Puente, Josué; Merino, Santiago; Tomás, Gustavo; Moreno, Juan; Morales, Judith; Lobato, Elisa; Martínez, Javier

    2011-02-01

    Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies.

  11. A new method for wireless video monitoring of bird nests

    Science.gov (United States)

    David I. King; Richard M. DeGraaf; Paul J. Champlin; Tracey B. Champlin

    2001-01-01

    Video monitoring of active bird nests is gaining popularity among researchers because it eliminates many of the biases associated with reliance on incidental observations of predation events or use of artificial nests, but the expense of video systems may be prohibitive. Also, the range and efficiency of current video monitoring systems may be limited by the need to...

  12. Influence of nest box environment on kit survival

    DEFF Research Database (Denmark)

    Lund, V.H.; Malmkvist, Jens

    2012-01-01

    . In conclusion, access to different nesting materials reduced the risk of dying in farm mink in relation with factors as e.g. nest quality and maternal behaviour. A decrease in kit mortality from 20% to 5% would give the Danish mink production a profound number of Danish kroner extra per year....

  13. Long-eared owls nesting in Badlands National Park

    Science.gov (United States)

    Deborah D. Paulson; Carolyn Hull Sieg

    1985-01-01

    Long-eared Owls nest at high densities locally over the Great Plains where suitable habitat is limited (Bent 1938), yet , according to Whitney et al. (1978), this species is rare to uncommon in South Dakota. Especially west of the Missouri River, few nesting records have been reported. This paper reports the occurrence of Long-eared Owls in the Badlands National Park...

  14. Nesting habitat and productivity of Swainson's Hawks in southeastern Arizona

    Science.gov (United States)

    Nishida, Catherine; Boal, Clint W.; DeStefano, Stephen; Hobbs, Royden J.

    2013-01-01

    We studied Swainson's Hawks (Buteo swainsoni) in southeastern Arizona to assess the status of the local breeding population. Nest success (≥1 young fledged) was 44.4% in 1999 with an average of 1.43 ± 0.09 (SE) young produced per successful pair. Productivity was similar in 2000, with 58.2% nesting success and 1.83 ± 0.09 fledglings per successful pair. Mesquite (Prosopis velutina) and cottonwood (Populus fremontii) accounted for >50% of 167 nest trees. Nest trees were taller than surrounding trees and random trees, and overall there was more vegetative cover at nest sites than random sites. This apparent requirement for cover around nest sites could be important for management of the species in Arizona. However, any need for cover at nest sites must be balanced with the need for open areas for foraging. Density of nesting Swainson's Hawks was higher in agriculture than in grasslands and desert scrub. Breeding pairs had similar success in agricultural and nonagricultural areas, but the effect of rapid and widespread land-use change on breeding distribution and productivity continues to be a concern throughout the range of the species.

  15. LOGGERHEAD SEA TURTLE LATE NESTING ECOLOGY IN VIRGINIA BEACH, VIRGINIA

    Science.gov (United States)

    T'he.loggerhead sea turtle (Caretta came is the only recurrent nesting species of sea turtle in southeastern Virginia (Lutcavage & Musick, 1985; Dodd, 1988). Inasmuch as the loggerhead is a federally threatened species, the opportunity to gather data on its nesting ecology is imp...

  16. Nesting behavior of Trypoxylon (Trypargilum agamemnom Richards (Hymenoptera: Crabronidae

    Directory of Open Access Journals (Sweden)

    MLT Buschini

    Full Text Available Nesting behaviour is extremely diversified among solitary nesting sphecids. Thus, the aim of this study was to describe the nesting behaviour of Trypoxylon agamemnon and discuss the advantages of guarding behaviour of males. It was conducted in the Parque Municipal das Araucárias, Guarapuava (PR, Brazil from October/2003 to July/2007. To describe the behaviour of T. agamemnon and construct its ethogram, daily observations were made, totalling 410:19 hours observation. Although the males of T. agamemnon stand guard close to the entrance of the nests, we concluded that this behaviour is not ensuring the protection of nests against parasitoids and that, probably, this behaviour ensures them the paternity, but further studies with microsatellite markers will be necessary to confirm this hypothesis.

  17. Nesting behavior of Trypoxylon (Trypargilum) agamemnom Richards (Hymenoptera: Crabronidae).

    Science.gov (United States)

    Buschini, M L T; Donatti, A J

    2012-05-01

    Nesting behaviour is extremely diversified among solitary nesting sphecids. Thus, the aim of this study was to describe the nesting behaviour of Trypoxylon agamemnon and discuss the advantages of guarding behaviour of males. It was conducted in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil from October/2003 to July/2007. To describe the behaviour of T. agamemnon and construct its ethogram, daily observations were made, totalling 410:19 hours observation. Although the males of T. agamemnon stand guard close to the entrance of the nests, we concluded that this behaviour is not ensuring the protection of nests against parasitoids and that, probably, this behaviour ensures them the paternity, but further studies with microsatellite markers will be necessary to confirm this hypothesis.

  18. Nest predation research: Recent findings and future perspectives

    Science.gov (United States)

    Chalfoun, Anna D.; Ibanez-Alamo, J. D.; Magrath, R. D.; Schmidt, Kenneth A.; Thomson, R. L.; Oteyza, Juan C.; Haff, T. M.; Martin, T.E.

    2016-01-01

    Nest predation is a key source of selection for birds that has attracted increasing attention from ornithologists. The inclusion of new concepts applicable to nest predation that stem from social information, eavesdropping or physiology has expanded our knowledge considerably. Recent methodological advancements now allow focus on all three players within nest predation interactions: adults, offspring and predators. Indeed, the study of nest predation now forms a vital part of avian research in several fields, including animal behaviour, population ecology, evolution and conservation biology. However, within nest predation research there are important aspects that require further development, such as the comparison between ecological and evolutionary antipredator responses, and the role of anthropogenic change. We hope this review of recent findings and the presentation of new research avenues will encourage researchers to study this important and interesting selective pressure, and ultimately will help us to better understand the biology of birds.

  19. Directed random polymers via nested contour integrals

    Science.gov (United States)

    Borodin, Alexei; Bufetov, Alexey; Corwin, Ivan

    2016-05-01

    We study the partition function of two versions of the continuum directed polymer in 1 + 1 dimension. In the full-space version, the polymer starts at the origin and is free to move transversally in R, and in the half-space version, the polymer starts at the origin but is reflected at the origin and stays in R-. The partition functions solve the stochastic heat equation in full-space or half-space with mixed boundary condition at the origin; or equivalently the free energy satisfies the Kardar-Parisi-Zhang equation. We derive exact formulas for the Laplace transforms of the partition functions. In the full-space this is expressed as a Fredholm determinant while in the half-space this is expressed as a Fredholm Pfaffian. Taking long-time asymptotics we show that the limiting free energy fluctuations scale with exponent 1 / 3 and are given by the GUE and GSE Tracy-Widom distributions. These formulas come from summing divergent moment generating functions, hence are not mathematically justified. The primary purpose of this work is to present a mathematical perspective on the polymer replica method which is used to derive these results. In contrast to other replica method work, we do not appeal directly to the Bethe ansatz for the Lieb-Liniger model but rather utilize nested contour integral formulas for moments as well as their residue expansions.

  20. Fermi Surface Nesting in UGe_2

    Science.gov (United States)

    Wang, F.; Allen, J. W.; Denlinger, J. D.; Rossnagel, Kai; Huxley, A. D.; Flouquet, J.

    2004-03-01

    UGe2 is of high current interest in connection with the possible role of ferromagnetic fluctuations in its pressure induced superconductivity, for which the Fermi surface (FS) is thought to be important. The band structure and FS contours of a single crystal have been measured using resonant angle-resolved photoemission near the U 5d to 5f edge. The measured dominant large sheet Fermi surface contour shows good agreement with magneto-oscillatory orbit frequencies, but with a much simpler diamond-like shape as compared to LDA and LDA+U band calculations. The measured FS topology is suggestive of a possible diagonal nesting condition different than previously proposed for SCDW models of the ferromagnetic transition(s) in UGe2 and allows assessment of FS topology-driven models of the ferromagnetic superconductor phase diagram.(e.g. K.G. Sandeman et al.), Phys. Rev. Lett. 90, 167005 (2003). Supported by the U.S. NSF at U. Mich. (DMR-03-02825) and by the DOE at the Advanced Light Source (DE-AC03-76SF00098).

  1. Nest Success and Cause-Specific Nest Failure of Grassland Passerines Breeding in Prairie Grazed by Livestock

    Science.gov (United States)

    This manuscript describes two years of field research on ground-nesting songbird species at Zumwalt Prairie Reserve, northeastern Oregon, USA. Cattle-grazing has long been suspected in declines of ground-nesting songbirds in grazed grassland, primarily due to increased trampling...

  2. Effects of timber size-class on predation of artificial nests in extensive forest

    Science.gov (United States)

    Richard M. DeGraaf; Per. Angelstam

    1993-01-01

    Depredation on artificial ground and cup nests in even-aged seedling/sapling, pole, and mature stands of continuous northern hardwood forest was studied in the White Mountain National Forest in New Hampshire, USA from May to June 1988. Track-board nests were used to identify predators of ground nests; plain ground nests and cup nests were used to investigate the...

  3. Contrasting Effects of Cattle Grazing Intensity on Upland-Nesting Duck Production at Nest and Field Scales in the Aspen Parkland, Canada

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Warren

    2008-12-01

    Full Text Available The Aspen Parkland of Canada is one of the most important breeding areas for temperate nesting ducks in North America. The region is dominated by agricultural land use, with approximately 9.3 million ha in pasture land for cattle grazing. However, the effects of using land for cattle grazing on upland-nesting duck production are poorly understood. The current study was undertaken during 2001 and 2002 to investigate how nest density and nesting success of upland-nesting ducks varied with respect to the intensity of cattle grazing in the Aspen Parkland. We predicted that the removal and trampling of vegetation through cattle grazing would reduce duck nest density. Both positive and negative responses of duck nesting success to grazing have been reported in previous studies, leading us to test competing hypotheses that nesting success would (1 decline linearly with grazing intensity or (2 peak at moderate levels of grazing. Nearly 3300 ha of upland cover were searched during the study. Despite extensive and severe drought, nest searches located 302 duck nests. As predicted, nest density was higher in fields with lower grazing intensity and higher pasture health scores. A lightly grazed field with a pasture score of 85 out of a possible 100 was predicted to have 16.1 nests/100 ha (95% CI = 11.7–22.1, more than five times the predicted nest density of a heavily grazed field with a pasture score of 58 (3.3 nests/100 ha, 95% CI = 2.2–4.5. Nesting success was positively related to nest-site vegetation density across most levels of grazing intensity studied, supporting our hypothesis that reductions in vegetation caused by grazing would negatively affect nesting success. However, nesting success increased with grazing intensity at the field scale. For example, nesting success for a well-concealed nest in a lightly grazed field was 11.6% (95% CI = 3.6–25.0%, whereas nesting success for a nest with the same level of nest-site vegetation in a heavily

  4. Nesting ecology of roseate spoonbills at Nueces Bay, Texas

    Science.gov (United States)

    White, D.H.; Mitchell, C.A.; Cromartie, E.

    1982-01-01

    We conducted a study in 1978-1980 of the nesting ecology of Roseate Spoonbills (Ajaia ajaja) in a relatively polluted environment at Nueces Bay, Texas. For 154 marked nests, the average clutch size was 3.0 eggs; 73% of the eggs hatched, and 87% of the nests were successful (hatched at least 1 young). The average nest success rate (total fledglings:total eggs) was 50% or 1.5 fledglings per total nests. Incubation began the day after the first egg was laid, and the incubation period for each egg was 22 days. Eggs hatched in the order that they were laid; the first and second eggs hatched on consecutive days, and the second, third, and fourth eggs hatched every other day. Nest composition and size were highly consistent, but nest placement varied considerably and was dependent on the vegetative configuration of the dredge-material islands. Growth rate of nestlings conformed to a 'standard' growth curve, where body weight of nestlings at fledging equaled that of adults. There was no difference in weight gain among siblings based on actual age. Nestlings fledged at about 6 weeks of age, when feather development was complete. At fledging, the bills of juveniles had almost reached adult width, but bill length was only 67% that of adults. In general, environmental pollutants were low (Nueces Bay, Texas, though the area is surrounded by industries and agricultural lands. Apparently, spoonbills are less sensitive to these contaminants than are other aquatic species

  5. Red-shouldered hawk nesting habitat preference in south Texas

    Science.gov (United States)

    Strobel, Bradley N.; Boal, Clint W.

    2010-01-01

    We examined nesting habitat preference by red-shouldered hawks Buteo lineatus using conditional logistic regression on characteristics measured at 27 occupied nest sites and 68 unused sites in 2005–2009 in south Texas. We measured vegetation characteristics of individual trees (nest trees and unused trees) and corresponding 0.04-ha plots. We evaluated the importance of tree and plot characteristics to nesting habitat selection by comparing a priori tree-specific and plot-specific models using Akaike's information criterion. Models with only plot variables carried 14% more weight than models with only center tree variables. The model-averaged odds ratios indicated red-shouldered hawks selected to nest in taller trees and in areas with higher average diameter at breast height than randomly available within the forest stand. Relative to randomly selected areas, each 1-m increase in nest tree height and 1-cm increase in the plot average diameter at breast height increased the probability of selection by 85% and 10%, respectively. Our results indicate that red-shouldered hawks select nesting habitat based on vegetation characteristics of individual trees as well as the 0.04-ha area surrounding the tree. Our results indicate forest management practices resulting in tall forest stands with large average diameter at breast height would benefit red-shouldered hawks in south Texas.

  6. Extreme sequential polyandry insures against nest failure in a frog.

    Science.gov (United States)

    Byrne, Phillip G; Keogh, J Scott

    2009-01-07

    Sequential polyandry may evolve as an insurance mechanism to reduce the risk of choosing a mate that is infertile, closely related, genetically inferior or incompatible, but polyandry also might insure against nest failure in unpredictable environments. Most animals are oviparous, and in species where males provide nest sites whose quality varies substantially and unpredictably, polyandrous females might insure offspring success by distributing their eggs across multiple nests. Here, we test this hypothesis in a wild population of an Australian terrestrial toadlet, a polyandrous species, where males construct nests and remain with broods. We found that females partitioned their eggs across the nests of two to eight males and that more polyandrous females gained a significant increase in mean offspring survivorship. Our results provide evidence for the most extreme case of sequential polyandry yet discovered in a vertebrate and also suggest that insurance against nest failure might favour the evolution of polyandry. We propose that insurance against nest failure might be widespread among oviparous taxa and provide an important explanation for the prevalence of sequential polyandry in nature.

  7. An object-oriented approach to nested data parallelism

    Science.gov (United States)

    Sheffler, Thomas J.; Chatterjee, Siddhartha

    1994-01-01

    This paper describes an implementation technique for integrating nested data parallelism into an object-oriented language. Data-parallel programming employs sets of data called 'collections' and expresses parallelism as operations performed over the elements of a collection. When the elements of a collection are also collections, then there is the possibility for 'nested data parallelism.' Few current programming languages support nested data parallelism however. In an object-oriented framework, a collection is a single object. Its type defines the parallel operations that may be applied to it. Our goal is to design and build an object-oriented data-parallel programming environment supporting nested data parallelism. Our initial approach is built upon three fundamental additions to C++. We add new parallel base types by implementing them as classes, and add a new parallel collection type called a 'vector' that is implemented as a template. Only one new language feature is introduced: the 'foreach' construct, which is the basis for exploiting elementwise parallelism over collections. The strength of the method lies in the compilation strategy, which translates nested data-parallel C++ into ordinary C++. Extracting the potential parallelism in nested 'foreach' constructs is called 'flattening' nested parallelism. We show how to flatten 'foreach' constructs using a simple program transformation. Our prototype system produces vector code which has been successfully run on workstations, a CM-2, and a CM-5.

  8. Interspecific nest parasitism by chukar on greater sage-grouse

    Science.gov (United States)

    Fearon, Michelle L.; Coates, Peter S.

    2014-01-01

    Nest parasitism occurs when a female bird lays eggs in the nest of another and the host incubates the eggs and may provide some form of parental care for the offspring (Lyon and Eadie 1991). Precocial birds (e.g., Galliformes and Anseriformes) are typically facultative nest parasites of both their own and other species (Lyon and Eadie 1991). This behavior increases a female’s reproductive success when she parasitizes other nests while simultaneously raising her own offspring. Both interspecific and conspecific nest parasitism have been well documented in several families of the order Galliformes, particularly the Phasianidae (Lyon and Eadie 1991, Geffen and Yom-Tov 2001, Krakauer and Kimball 2009). The Chukar (Alectoris chukar) has been widely introduced as a game bird to western North America from Eurasia and is now well established within the Great Basin from northeastern California east to Utah and north to Idaho and Oregon (Christensen 1996). Over much of this range the Chukar occurs with other phasianids, including the native Greater Sage-Grouse (Centrocercus urophasianus), within sagebrush (Artemisia spp.) steppe (Christensen 1996, Schroeder et al. 1999, Connelly et al. 2000). Chukar typically exploit a broader range of habitats than do sage-grouse, but both species use the same species of sagebrush and other shrubs for nesting cover (Christensen 1996, Schroeder et al. 1999). Chukar are known to parasitize nests of other individuals of their own species (Geffen and Yom-Tov 2001), but we are unaware of reported evidence that Chukar may parasitize nests of sage-grouse. Here we describe a case of a Chukar parasitizing a sage-grouse nest in the sagebrush steppe of western Nevada.

  9. Effect of balanced phacoemulsification tip on the outcomes of torsional phacoemulsification using an active-fluidics system.

    Science.gov (United States)

    Khokhar, Sudarshan; Aron, Neelima; Sen, Sagnik; Pillay, Ganesh; Agarwal, Esha

    2017-01-01

    To compare the outcomes of torsional phacoemulsification with a new balanced tip (Intrepid) and a conventional tip (Kelman) using a single active-fluidics torsional phacoemulsification machine (Centurion). Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. Prospective comparative case-control study. Patients with senile cataract had torsional phacoemulsification with the Kelman conventional tip or the new Intrepid balanced tip using the active-fluidics torsional machine. Intraoperative parameters, such as cumulative dissipated energy (CDE), total ultrasound (US) time, torsion use time, torsion amplitude, aspiration time, and fluid use, were noted and compared. Endothelial cell loss and central corneal thickness (CCT) changes were evaluated at 1 month. The new tip showed significantly less CDE, total US time, torsion amplitude, aspiration time, and fluid use (8.55 ± 6.9 [SD], 33.59 ± 28.12 seconds, 37.8 ± 13.42, 173.19 ± 47.26 seconds, and 66.59 ± 20.44 mL, respectively) than the conventional tip (13.47 ± 10.65, 42.8 ± 33.46 seconds, 42.58 ± 16.38, 202.25 ± 71.28 seconds, and 97.14 ± 36.86 mL, respectively) (P < .01), especially in higher grades of cataract. Anterior capsulorhexis margin tear occurred in 2 patients with the new tip. There were no corneal burns in either group. The mean endothelial cell loss and the percentage change in CCT were not significantly different at 1 month. The new balanced tip performed phacoemulsification more efficiently, especially in hard cataracts requiring higher energy and prolonged phacoemulsification time. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Archiving California’s historical duck nesting data

    Science.gov (United States)

    Ackerman, Joshua T.; Herzog, Mark P.; Brady, Caroline; Eadie, John M.; Yarris, Greg S.

    2015-07-14

    The U.S. Geological Survey (USGS), in partnership with the California Waterfowl Association (CWA) and other organizations, have compiled large datasets on the nesting ecology and management of dabbling ducks and associated upland nesting birds (Northern Harriers [Circus cyaneus], Short-eared Owls [Asio flammeus], Ring-necked Pheasants [Phasianus colchicus], and American Bitterns [Botaurus lentiginosus]) throughout California on Federal Refuges, State Wildlife Areas, and private lands, some participating in State and Federal habitat programs. These datasets encompass several long-term monitoring programs at multiple sites throughout California, and include data from more than 26,000 nests and span nearly 30 years.

  11. Nested Hilbert schemes on surfaces: Virtual fundamental class

    DEFF Research Database (Denmark)

    Gholampour, Amin; Sheshmani, Artan; Yau, Shing-Tung

    2017-01-01

    We construct natural virtual fundamental classes for nested Hilbert schemes on a nonsingular projective surface S. This allows us to define new invariants of S that recover some of the known important cases such as Poincare invariants of Durr-Kabanov-Okonek and the stable pair invariants of Kool......-Thomas. In the case of the nested Hilbert scheme of points, we can express these invariants in terms of integrals over the products of Hilbert scheme of points on S, and relate them to the vertex operator formulas found by Carlsson-Okounkov. The virtual fundamental classes of the nested Hilbert schemes play a crucial...

  12. Spatiotemporal patterns of duck nest density and predation risk: a multi-scale analysis of 18 years and more than 10,000 nests

    Science.gov (United States)

    Ringelman, Kevin M.; Eadie, John M.; Ackerman, Joshua T.; Sih, Andrew; Loughman, Daniel L.; Yarris, Gregory S.; Oldenburger, Shaun L.; McLandress, M. Robert

    2017-01-01

    Many avian species are behaviorally-plastic in selecting nest sites, and may shift to new locations or habitats following an unsuccessful breeding attempt. If there is predictable spatial variation in predation risk, the process of many individuals using prior experience to adaptively change nest sites may scale up to create shifting patterns of nest density at a population level. We used 18 years of waterfowl nesting data to assess whether there were areas of consistently high or low predation risk, and whether low-risk areas increased, and high-risk areas decreased in nest density the following year. We created kernel density maps of successful and unsuccessful nests in consecutive years and found no correlation in predation risk and no evidence for adaptive shifts, although nest density was correlated between years. We also examined between-year correlations in nest density and nest success at three smaller spatial scales: individual nesting fields (10–28 ha), 16-ha grid cells and 4-ha grid cells. Here, results were similar across all scales: we found no evidence for year-to-year correlation in nest success but found strong evidence that nest density was correlated between years, and areas of high nest success increased in nest density the following year. Prior research in this system has demonstrated that areas of high nest density have higher nest success, and taken together, our results suggest that ducks may adaptively select nest sites based on the local density of conspecifics, rather than the physical location of last year's nest. In unpredictable environments, current cues, such as the presence of active conspecific nests, may be especially useful in selecting nest sites. The cues birds use to select breeding locations and successfully avoid predators deserve continued attention, especially in systems of conservation concern.

  13. Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe?

    Science.gov (United States)

    Suárez-Rodríguez, Monserrat; López-Rull, Isabel; Garcia, Constantino Macías

    2013-02-23

    Birds are known to respond to nest-dwelling parasites by altering behaviours. Some bird species, for example, bring fresh plants to the nest, which contain volatile compounds that repel parasites. There is evidence that some birds living in cities incorporate cigarette butts into their nests, but the effect (if any) of this behaviour remains unclear. Butts from smoked cigarettes retain substantial amounts of nicotine and other compounds that may also act as arthropod repellents. We provide the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests. The amount of cellulose acetate from butts in nests of two widely distributed urban birds was negatively associated with the number of nest-dwelling parasites. Moreover, when parasites were attracted to heat traps containing smoked or non-smoked cigarette butts, fewer parasites reached the former, presumably due to the presence of nicotine. Because urbanization changes the abundance and type of resources upon which birds depend, including nesting materials and plants involved in self-medication, our results are consistent with the view that urbanization imposes new challenges on birds that are dealt with using adaptations evolved elsewhere.

  14. Interaction between the solitary bee Chelostoma florisomne and its nest parasite Sapyga clavicornis-empty cells reduce the impact of parasites

    DEFF Research Database (Denmark)

    Munster-Swendsen, Mikael; Calabuig, Isabel

    2000-01-01

    Chelostoma, empty cells, interaction, mortality, nest architecture, nest parasite, protection, Sapyga, solitary bee......Chelostoma, empty cells, interaction, mortality, nest architecture, nest parasite, protection, Sapyga, solitary bee...

  15. 1990 Flathead Valley duck nesting study progress report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This informal progress report describes predator removal practices in the Lake County area, and observed waterfowl nest success. Species-specific data are...

  16. Inkjet printing of silk nest arrays for cell hosting.

    Science.gov (United States)

    Suntivich, Rattanon; Drachuk, Irina; Calabrese, Rossella; Kaplan, David L; Tsukruk, Vladimir V

    2014-04-14

    An inkjet printing approach is presented for the facile fabrication of microscopic arrays of biocompatible silk "nests" capable of hosting live cells for prospective biosensors. The patterning of silk fibroin nests were constructed by the layer-by-layer (LbL) assembly of silk polyelectrolytes chemically modified with poly-(l-lysine) and poly-(l-glutamic acid) side chains. The inkjet-printed silk circular regions with a characteristic "nest" shape had diameters of 70-100 μm and a thickness several hundred nanometers were stabilized by ionic pairing and by the formation of the silk II crystalline secondary structure. These "locked-in" silk nests remained anchored to the substrate during incubation in cell growth media to provide a biotemplated platform for printing-in, immobilization, encapsulation and growth of cells. The process of inkjet-assisted printing is versatile and can be applied on any type of substrate, including rigid and flexible, with scalability and facile formation.

  17. 1993 waterfowl nesting success on Fish Springs National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report on an investigation of nesting success and factors affecting it on Fish Springs National Wildlife Refuge. Baseline information on trust species within the...

  18. Wading bird nesting survey Fish Springs National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report discusses results of a wading bird survey conducted at Fish Springs National Wildlife Refuge. The objectives of the survey include; 1) quantify nest site...

  19. 2005 nest success data : Klettke WPA predator exclosure

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report summarizing nest success at Klettke Waterfowl Production Area predator exclosure on Kulm wetland Management District in 2005. In 2005, the Klettke predator...

  20. Contaminant exposure of white pelicans nesting at Anaho Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reproductive success of American white pelicans (Pelecanus erythrorhynchus) was monitored at a nesting colony on Anaho Island, Pyramid Lake, Nevada in 1996. Eggs...

  1. Bald Eagle Summary Report for New York Nesting Territories 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Observations at New York bald eagle nest sites one, three and four in Livingston, Genesee, and Seneca Counties respectively, continued during the 1991 breeding...

  2. Application of nested sampling in statistical physics: the Potts model

    CERN Document Server

    Pfeifenberger, Manuel J

    2016-01-01

    We present a systematic benchmark study of the nested sampling algorithm on the basis of the Potts model. This model exhibits a first order phase transition for $q>4$ at the critical temperature. The numerical evaluation of the partition function and thermodynamic observables, which involves high dimensional sums of sharply structured multi-modal density functions, represents a major challenge to most standard numerical techniques, such as Markov Chain Monte Carlo. Nested sampling, on the other hand, is particularly suited for such problems. In this paper we will employ both, nested sampling and thermodynamic integration to evaluate the partition function of the Potts model. In both cases individual moves are based on Swendsen-Wang updates. A autocorrelation time analysis of both algorithms shows that the severe slowing down of thermodynamic integration around the critical temperature does not occur in nested sampling. In addition we show, how thermodynamic variables can be computed with high accuracy from th...

  3. The Food and nesting Habits of the Bald Eagle

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the observations of the author who watched a bald eagle and studied its food habits at two nests. At the time of the report, the bald eagle...

  4. Bald Eagle Summary Report for New York Nesting Territories 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Observations at New York bald eagle nest sites one, three and four in Livingston, Genesee, and Seneca Counties respectively, continued during the 1990 breeding...

  5. Nest losses in grazed vs. ungrazed waterfowl habitat

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A fair number of managers, with student help, have just completed a series of dummy nest studies which sampled grazed and ungrazed habitat. I have examined 40...

  6. History of Waterfowl Nesting on the Patuxent Research Center

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary of waterfowl counts, waterfowl research, waterfowl nesting, and waterfowl records at Patuxent Research Refuge from 1963 through 2008, as...

  7. Medium Range Forecast (MRF) and Nested Grid Model (NGM)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Nested Grid Model (NGM) and Medium Range Forecast (MRF) Archive is historical digital data set DSI-6140, archived at the NOAA National Centers for Environmental...

  8. 1970 American Eagle Nest Survey of the Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1970 nesting season for the Bald Eagle in the Chesapeake area to include Virginia and Maryland. The 1970 results are most disappointing since...

  9. Bald Eagle Summary Report for New York Nesting Territories 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Observations at New York bald eagle nest sites one, three and four in Livingston, Genesee, and Seneca Counties respectively, continued during the 1989 breeding...

  10. Inventory and monitoring of red-cockaded woodpecker Nesting

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report provides nesting monitoring and group size summary data associated with the red-cockaded woodpecker population at Noxubee NWR in 2012.

  11. EXTREME POINTS IN DIAGONAL-DISJOINT IDEALS OF NEST ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    董浙; 鲁世杰

    2002-01-01

    In this paper, the extreme points of the unit ball of diagonal-disjoint ideals in nest algebras are characterized completely; Furthermore, it is shown that every extreme point of the unit ball of 2 has essential-norm one.

  12. [Proposal] Loggerhead sea turtle nest monitoring on seven refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this project is to continue FWS involvement in the long-term, consistent monitoring of loggerhead sea turtle nesting to assess changes in phenological...

  13. Shorebird Nesting Success Report : Bear River Migratory Bird Refuge : 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This preliminary study was initiated to establish a baseline of nesting success for one of the most important breeding sites of shorebirds within the Greater Salt...

  14. 1982 Bald Eagle Nest Survey, Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1982 nesting season for the Bald Eagle in the Chesapeake area to include Virginia, Maryland and Delaware. For the third year in succession we have...

  15. Black Tern Nesting, Missisquoi National Wildlife Refuge, 2009-2014

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Black tern breeding pair surveys have been conducted in Vermont every year since 1990, except during 2006. Initially, there were 3 separate nesting populations of...

  16. Effects Of Predator Exclosures On Nesting Success Of Killdeer

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Nests of shorebirds are often destroyed by predators and in some instances predation may cause severe local declines in breeding success and in size of a breeding...

  17. Proposal - Inventory and Monitoring for Red-cockaded Woodpecker Nesting

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Proposal is to monitor the nesting success and productivity of the red-cockaded woodpecker population at the Sam D. Hamilton Noxubee National Wildlife Refuge during...

  18. Nesting birds of the Malheur environmental field station

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this paper is to expose the reader to the various birds nesting on the Malheur environmental field station (MEFS). Each species will be discussed...

  19. Variation in nesting behavior of eight species of spider mites, Stigmaeopsis having sociality

    Science.gov (United States)

    Saito, Yutaka; Zhang, Yan-Xuan; Mori, Kotaro; Ito, Katsura; Sato, Yukie; Chittenden, Anthony R.; Lin, Jian-Zhen; Chae, Younghae; Sakagami, Takane; Sahara, Ken

    2016-10-01

    Nesting behavior is considered to be an important element of social living in animals. The spider mites belonging to the genus Stigmaeopsis spend their lives within nests produced from silk threads. Several of these species show cooperative sociality, while the others are subsocial. In order to identify the origins of this social behavior, comparisons of nest sizes, nesting behaviors (making nests continuously or separately), and their associated traits (fecal deposition patterns) were made for eight cogeneric Stigmaeopsis species showing various levels of social development. All of these species inhabit bamboo plants (Poaceae). We initially addressed the proximate factor of nest size variation. The variation in nest size of the eight species corresponded well with the variation in dorsal seta sc1 length, suggesting that nest size variation among species may have a genetic basis. The time spent within a nest (nest duration) increased with nest size on the respective host plants. Nest arrangement patterns varied among species showing different sized nests: Large nest builders continuously extended their nests, while middle and small nest-building species built new separate nests, which resulted in different social interaction times among species, and is thought to be closely related to social development. Fecal deposition behaviors also varied among Stigmaeopsis species, suggesting diversity in anti-predatory adaptations. Finally, we discuss how the variation in sociality observed within this genus is likely the result of nest size variation that initially evolved as anti-predator strategies.

  20. Study of thermo-fluidic behavior of micro-droplet in inkjet-based micro manufacturing processes

    Science.gov (United States)

    Das, Raju; Mahapatra, Abhijit; Ball, Amit Kumar; Roy, Shibendu Shekhar; Murmu, Naresh Chandra

    2017-06-01

    Inkjet printing technology, a maskless, non-contact patterning operation, which has been a revelation in the field of micro and nano manufacturing for its use in the selective deposition of desired materials. It is becoming an exciting alternative technology such as lithography to print functional material on to a substrate. Selective deposition of functional materials on desired substrates is a basic requirement in many of the printing based micro and nano manufacturing operations like the fabrication of microelectronic devices, solar cell, Light-emitting Diode (LED) research fields like pharmaceutical industries for drug discovery purposes and in biotechnology to make DNA microarrays. In this paper, an attempt has been made to design and develop an indigenous Electrohydrodynamic Inkjet printing system for micro fabrication and to study the interrelationships between various thermos-fluidic parameters of the ink material in the printing process. The effect of printing process parameters on printing performance characteristics has also been studied. And the applicability of the process has also been experimentally demonstrated. The experimentally found results were quite satisfactory and accordance to its applicability.

  1. Steady cone-jet mode in compound-fluidic electro-flow focusing for fabricating multicompartment microcapsules

    Science.gov (United States)

    Si, Ting; Yin, Chuansheng; Gao, Peng; Li, Guangbin; Ding, Hang; He, Xiaoming; Xie, Bin; Xu, Ronald X.

    2016-01-01

    A compound-fluidic electro-flow focusing (CEFF) process is proposed to produce multicompartment microcapsules. The central device mainly consists of a needle assembly of two parallel inner needles and one outer needle mounted in a gas chamber with their tips facing a small orifice at the bottom of the chamber. As the outer and the inner fluids flow through the needle assembly, a high-speed gas stream elongates the liquid menisci in the vicinity of the orifice entrance. An electric field is further integrated into capillary flow focusing to promote the formation of steady cone-jet mode in a wide range of operation parameters. The multiphase liquid jet is broken up into droplets due to perturbation propagation along the jet surface. To estimate the diameter of the multiphase liquid jet as a function of process parameters, a modified scaling law is derived and experimentally validated. Microcapsules of around 100 μm with an alginate shell and multiple cores at a production rate of 103-105 per second are produced. Technical feasibility of stimulation triggered coalescence and drug release is demonstrated by benchtop experiments. The proposed CEFF process can be potentially used to encapsulate therapeutic agents and biological cargos for controlled micro-reaction and drug delivery.

  2. Modeling the Peano fluidic muscle and the effects of its material properties on its static and dynamic behavior

    Science.gov (United States)

    Veale, Allan Joshua; Xie, Sheng Quan; Anderson, Iain Alexander

    2016-06-01

    The promise of wearable assistive robotics cannot be realized without the development of actuators that mimic the behavior and form of biological muscles. Planar fluidic muscles known as Peano muscles or pouch motors have the potential to provide the high force and compliance of McKibben pneumatic artificial muscles with the low threshold pressure of pleated pneumatic artificial muscles. Yet they do so in a soft and slim form that can be discreetly distributed over the human body. This work is an investigation into the empirical modeling of the Peano muscle, the effect of its material on its performance, and its capabilities and limitations. We discovered that the Peano muscle could provide responsive and discreet actuation of soft and rigid bodies requiring strains between 15% and 30%. Ideally, they are made of non-viscoelastic materials with high tensile and low bending stiffnesses. While Sarosi et al’s empirical model accurately captures its static behavior with an root mean square error of 10.2 N, their dynamic model overestimates oscillation frequency and damping. We propose that the Peano muscle be modeled by a parallel ideal contractile unit and viscoelastic element, both in series with another viscoelastic element.

  3. Static investigation of two fluidic thrust-vectoring concepts on a two-dimensional convergent-divergent nozzle

    Science.gov (United States)

    Wing, David J.

    1994-01-01

    A static investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel of two thrust-vectoring concepts which utilize fluidic mechanisms for deflecting the jet of a two-dimensional convergent-divergent nozzle. One concept involved using the Coanda effect to turn a sheet of injected secondary air along a curved sidewall flap and, through entrainment, draw the primary jet in the same direction to produce yaw thrust vectoring. The other concept involved deflecting the primary jet to produce pitch thrust vectoring by injecting secondary air through a transverse slot in the divergent flap, creating an oblique shock in the divergent channel. Utilizing the Coanda effect to produce yaw thrust vectoring was largely unsuccessful. Small vector angles were produced at low primary nozzle pressure ratios, probably because the momentum of the primary jet was low. Significant pitch thrust vector angles were produced by injecting secondary flow through a slot in the divergent flap. Thrust vector angle decreased with increasing nozzle pressure ratio but moderate levels were maintained at the highest nozzle pressure ratio tested. Thrust performance generally increased at low nozzle pressure ratios and decreased near the design pressure ratio with the addition of secondary flow.

  4. Renewable Surface Fluorescence Sandwich Immunoassay Biosensor for Rapid Sensitive Botulinum Toxin Detection in an Automated Fluidic Format

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Warner, Marvin G.; Ozanich, Richard M.; Miller, Keith D.; Colburn, Heather A.; Dockendorff, Brian P.; Antolick, Kathryn C.; Anheier, Norman C.; Lind, Michael A.; Lou, Jianlong; Marks, James D.; Bruckner-Lea, Cindy J.

    2009-03-05

    A renewable surface biosensor for rapid detection of botulinum toxin is described based on fluidic automation of a fluorescence sandwich immunoassay, using a recombinant fragment of the toxin heavy chain as a structurally valid simulant. Monoclonal antibodies AR4 and RAZ1 bind to separate epitopes of both this fragment and the holotoxin. The AR4 antibody was covalently bound to Sepharose beads and used as the capture antibody. A rotating rod flow cell was used to capture these beads delivered as a suspension by the sequential injection flow system, creating a 3.6 microliter column. After perfusing the bead column with sample and washing away the matrix, the column was perfused with Alexa 647 dye-labeled RAZ1 antibody as the reporter. Optical fibers coupled to the rotating rod flow cell at a 90 degree angle to one another delivered excitation light from a HeNe laser and collected fluorescent emission light for detection. After each measurement, the used sepharose beads are released and replaced with fresh beads. In a rapid screening approach to sample analysis, the toxin simulant was detected to concentrations of 10 pM in less than 20 minutes.

  5. Intensified surface enhanced Raman signal of a graphene monolayer on a plasmonic substrate through the use of fluidic dielectrics

    Science.gov (United States)

    Mahigir, A.; Gartia, M. R.; Chang, T.-W.; Liu, G. L.; Veronis, G.

    2017-02-01

    It has been shown that surface enhanced Raman spectroscopy (SERS) has many promising applications in ultrasensitive detection of Raman signal of substances. However, optimizing the enhancement in SERS signal for different applications typically requires several levels of fabrication of active plasmonic SERS substrates. In this paper, we report the enhancement of SERS signal of a single layer of graphene located on a plasmonic nano-Lycurgus cup array after placing water droplets on it. The experimental data shows that addition of water droplets can enhance the SERS signal of the single layer of graphene about 10 times without requiring any modifications to the nano-Lycurgus cup array. Using fullwave electromagnetic simulations, we show that addition of water droplets enhances the local electric field at the graphene layer, resulting in stronger light-graphene interaction at the excitation pump laser wavelength. We also show that the addition of water droplets on the graphene layer enables us to modify the band diagram of the structure, in order to enhance the local density of optical states at the Raman emission wavelengths of the graphene layer. Numerical calculations of both the excitation field enhancement at the location of the graphene layer, and the emission enhancement due to enhanced local density of optical states, support the experimental results. Our results demonstrate an approach to boost the SERS signal of a target material by controlling the band diagram of the active nanostructured SERS substrate through the use of fluidic dielectrics. These results could find potential applications in biomedical and environmental technologies.

  6. Adapted nested force-gradient integrators for the Schwinger model

    CERN Document Server

    Shcherbakov, Dmitry; Günther, Michael; Finkenrath, Jacob; Knechtli, Francesco; Peardon, Michael

    2016-01-01

    We study a novel class of numerical integrators, the adapted nested force-gradient schemes, used within the molecular dynamics step of the Hybrid Monte Carlo (HMC) algorithm. We test these methods in the Schwinger model on the lattice, a well known benchmark problem. We derive the analytical basis of nested force-gradient type methods and demonstrate the advantage of the proposed approach, namely reduced computational costs compared with other numerical integration schemes in HMC.

  7. Nest sanitation elicits egg discrimination in cuckoo hosts.

    Science.gov (United States)

    Yang, Canchao; Chen, Min; Wang, Longwu; Liang, Wei; Møller, Anders Pape

    2015-11-01

    Nest sanitation is a nearly universal behavior in birds, while egg discrimination is a more specific adaptation that has evolved to counter brood parasitism. These two behaviors are closely related with nest sanitation being the ancestral behavior, and it has been hypothesized to constitute a preadaptation for egg discrimination. However, previous studies found little evidence to support this hypothesis. Here, we conducted an empirical test of the association between nest sanitation and egg discrimination in the barn swallow (Hirundo rustica) by inserting a single non-mimetic model egg or a non-mimetic model egg plus half a peanut shell into host nests. Compared to the rejection rate of single model eggs, barn swallows significantly increased egg rejection frequency if a half peanut shell was simultaneously introduced. Our result for the first time shows the impact of nest sanitation on egg discrimination and demonstrates that nest sanitation can elicit egg discrimination in hosts of brood parasites. This study provided evidence for nest sanitation being a preadaptation to egg discrimination by facilitating egg rejection, thereby significantly advancing our understanding of avian cognition of foreign objects. Furthermore, we suggest that egg discrimination behavior in many accepters and intermediate rejecters may be lost or diluted. Such egg discrimination can be elicited and restored after nest sanitation, implying a sensitive and rapid phenotypic response to increased risk of parasitism. Our study offers a novel perspective for investigating the role of so-called intermediate rejecter individuals or species in the long-term coevolutionary cycle between brood parasites and their hosts.

  8. Nesting behavior of Podium denticulatum Smith (Hymenoptera: Sphecidae).

    Science.gov (United States)

    Ribeiro, Favi; Garófalo, Carlos A

    2010-01-01

    The nesting behavior of Podium denticulatum Smith was studied on the campus of Ribeirão Preto of the Universidade de São Paulo, SP, Brazil, from September 2003 to August 2005. The wasps established their nests in bamboo canes ranging from 11.4 cm to 26.2 cm in length and from 0.7 cm to 1.8 cm in internal diameter. Podium denticulatum nested almost exclusively in the hot and wet season (September-April), producing at least five generations per year. The cell provisioning was made with adult and nymphal cockroaches (Blattellidae) which were arranged venter-up and with the head inward toward the inner end of the cell. The construction of a temporary closure occurred in cells that took more than one day to be provisioned. The cells provisioned with a greater number of prey were more likely to produce females than males. The nests included 1-6 brood cells separated by mud partitions and arranged in a linear series. The innermost cells of the nests produced females, and the outermost cells produced males. Nests were parasitized by Eulophidae (Melittobia sp.), Chrysididae and Tachinidae.

  9. Plastic and the nest entanglement of urban and agricultural crows.

    Directory of Open Access Journals (Sweden)

    Andrea K Townsend

    Full Text Available Much attention has been paid to the impacts of plastics and other debris on marine organisms, but the effects of plastic on terrestrial organisms have been largely ignored. Detrimental effects of terrestrial plastic could be most pronounced in intensively human-modified landscapes (e.g., urban and agricultural areas, which are a source of much anthropogenic debris. Here, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American crow (Corvus brachyrhynchos, a North American species that breeds in both urban and agricultural landscapes. We monitored 195 nestlings in 106 nests across an urban and agricultural gradient in the Sacramento Valley, California, USA. We found that 85.2% of crow nests contained anthropogenic material, and 11 of 195 nestlings (5.6% were entangled in their nests. The length of the material was greater in nests in agricultural territories than in urban territories, and the odds of entanglement increased 7.55 times for each meter of anthropogenic material in the nest. Fledging success was significantly lower for entangled than for unentangled nestlings. In all environments, particularly urban, agricultural, and marine, careful disposal of potential hazards (string, packing and hay bale twine, balloon ribbon, wire, fishing line could reduce the occurrence of entanglement of nestling birds.

  10. Plastic and the nest entanglement of urban and agricultural crows.

    Science.gov (United States)

    Townsend, Andrea K; Barker, Christopher M

    2014-01-01

    Much attention has been paid to the impacts of plastics and other debris on marine organisms, but the effects of plastic on terrestrial organisms have been largely ignored. Detrimental effects of terrestrial plastic could be most pronounced in intensively human-modified landscapes (e.g., urban and agricultural areas), which are a source of much anthropogenic debris. Here, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American crow (Corvus brachyrhynchos), a North American species that breeds in both urban and agricultural landscapes. We monitored 195 nestlings in 106 nests across an urban and agricultural gradient in the Sacramento Valley, California, USA. We found that 85.2% of crow nests contained anthropogenic material, and 11 of 195 nestlings (5.6%) were entangled in their nests. The length of the material was greater in nests in agricultural territories than in urban territories, and the odds of entanglement increased 7.55 times for each meter of anthropogenic material in the nest. Fledging success was significantly lower for entangled than for unentangled nestlings. In all environments, particularly urban, agricultural, and marine, careful disposal of potential hazards (string, packing and hay bale twine, balloon ribbon, wire, fishing line) could reduce the occurrence of entanglement of nestling birds.

  11. Nesting biology of Centris (Centris aenea Lepeletier (Hymenoptera, Apidae, Centridini

    Directory of Open Access Journals (Sweden)

    Cândida Maria Lima Aguiar

    2003-12-01

    Full Text Available Nesting activity of Centris aenea Lepeletier, 1841 was studied in two Brazilian habitats, Caatinga (Monte Santo, Bahia and Cerrado (Palmeiras, Bahia and Luiz Antônio, São Paulo. Nests were excavated in the ground and did not tend to be aggregated together at the two sites, but at Palmeiras, nests were in a large aggregation. Nest architecture consists of a single unbranched tunnel, sloping to vertical, which leads to a linear series of four cells, placed from 8 to 26 cm in depth. Cells are urn-shaped with a rounded base, and their cell caps have a central hollow process, as in other Centridini. Nest architecture of C. aenea was compared to other species of Centris Fabricius, 1804. Provisions are composed of a pollen mass covered by a thin liquid layer on which the egg is placed. Females were observed gathering oil on Mcvaughia bahiana W.R. Anderson flowers from October to March in the Caatinga, and on Byrsonima intermedia A.Juss. as well as other Malpighiaceae species from August to December in the Cerrado. Pollen is gathered by buzzing flowers of Solanaceae, Caesalpiniaceae, Malpighiaceae, and Ochnaceae. Several nectar sources were recorded. There is indirect evidence that Mesoplia sp. parasitizes nests of C. aenea in the Cerrado.

  12. Japanese queenless ants, Pristomyrmex punctatus, prefer the traces of both nestmates and strangers in nest selection.

    Science.gov (United States)

    Satow, Show; Saitow, Yuka; Yamaki, Shōtarō; Hirota, Tadao

    2013-07-01

    Conspecific avoidance may influence the spatial distribution of colonies in some ants. House-hunting ants (Temnothorax albipennis) avoid nesting in areas where non-nestmates have nested previously. However, no reports are available on conspecific avoidance during nest selection in other ants. In the present study, we investigated nest selection in another nomadic species, the Japanese queenless ant, Pristomyrmex punctatus. Two-choice tests revealed that, similar to house-hunting ants, P. punctatus preferred nests soiled by nestmates to clean nests. However, unlike house-hunting ants, P. punctatus also preferred nests soiled by non-nestmates to a clean nest. Given the choice between a nest soiled by nestmates and one soiled by strangers, P. punctatus, unlike house-haunting ants, showed no significant preference. Thus, conspecific avoidance in nest selection was not observed in P. punctatus. Interspecific differences in ecological factors may drive the evolution of different nest selection strategies.

  13. Striped-tailed Yellow-finch nesting success in abandoned mining pits from central Brazilian cerrado

    Directory of Open Access Journals (Sweden)

    DT. Gressler

    Full Text Available Suitability of degraded areas as breeding habitats can be tested through assessment of nest predation rates. In this study we estimated nest success in relation to several potential predictors of nest survival in the Stripe-tailed Yellow-finch (Sicalis citrina breeding in abandoned mining pits at Brasília National Park. We monitored 73 nests during the 2007-breeding season. Predation was the main cause of nest failure (n = 48, 66%; while six nests were abandoned (8% and 19 nests produced young (26%. Mayfield’s daily survival rates and nest success were 0.94 and 23%, respectively. Our results from nest survival models on program MARK indicated that daily survival rates increase linearly towards the end of the breeding season and decrease as nests aged. None of the nest individual covariates we tested - nest height, nest size, nest substrate, and edge effect - were important predictors of nest survival; however, nests placed on the most common plant tended to have higher survival probabilities. Also, there was no observer effect on daily survival rates. Our study suggests that abandoned mining pits may be suitable alternative breeding habitats for Striped-tailed Yellow-finches since nest survival rates were similar to other studies in the central cerrado region.

  14. A review of the nest protection hypothesis: does inclusion of fresh green plant material in birds' nests reduce parasite infestation?

    Science.gov (United States)

    Scott-Baumann, James F; Morgan, Eric R

    2015-07-01

    The use of aromatic plants and their essential oils for ectoparasite treatment is a field of growing interest. Several species of birds regularly introduce aromatic herbs into their nests putatively to reduce parasites. The behaviour is most often seen in cavity nesting birds and after nest building has finished. The plants are included in a non-structural manner and are often strongly aromatic. Various different hypotheses have been proposed regarding the function of this behaviour; from the plants altering some non-living factor in the nest (crypsis, water loss and insulation hypotheses) to them being involved in mate selection (mate hypothesis) or even having a beneficial effect, direct or indirect, on chicks (drug or nest protection hypothesis, NPH). Many studies have been carried out over the years observing and experimentally testing these hypotheses. This review focuses on studies involving the most popular of these hypotheses, the NPH: that plants decrease nest parasites or pathogens, thereby conveying positive effects to the chicks, allowing the behaviour to evolve. Studies providing observational evidence towards this hypothesis and those experimentally testing it are discussed.

  15. Variation in clutch size in relation to nest size in birds

    Science.gov (United States)

    Møller, Anders P; Adriaensen, Frank; Artemyev, Alexandr; Bańbura, Jerzy; Barba, Emilio; Biard, Clotilde; Blondel, Jacques; Bouslama, Zihad; Bouvier, Jean-Charles; Camprodon, Jordi; Cecere, Francesco; Charmantier, Anne; Charter, Motti; Cichoń, Mariusz; Cusimano, Camillo; Czeszczewik, Dorota; Demeyrier, Virginie; Doligez, Blandine; Doutrelant, Claire; Dubiec, Anna; Eens, Marcel; Eeva, Tapio; Faivre, Bruno; Ferns, Peter N; Forsman, Jukka T; García-Del-Rey, Eduardo; Goldshtein, Aya; Goodenough, Anne E; Gosler, Andrew G; Góźdź, Iga; Grégoire, Arnaud; Gustafsson, Lars; Hartley, Ian R; Heeb, Philipp; Hinsley, Shelley A; Isenmann, Paul; Jacob, Staffan; Järvinen, Antero; Juškaitis, Rimvydas; Korpimäki, Erkki; Krams, Indrikis; Laaksonen, Toni; Leclercq, Bernard; Lehikoinen, Esa; Loukola, Olli; Lundberg, Arne; Mainwaring, Mark C; Mänd, Raivo; Massa, Bruno; Mazgajski, Tomasz D; Merino, Santiago; Mitrus, Cezary; Mönkkönen, Mikko; Morales-Fernaz, Judith; Morin, Xavier; Nager, Ruedi G; Nilsson, Jan-Åke; Nilsson, Sven G; Norte, Ana C; Orell, Markku; Perret, Philippe; Pimentel, Carla S; Pinxten, Rianne; Priedniece, Ilze; Quidoz, Marie-Claude; Remeš, Vladimir; Richner, Heinz; Robles, Hugo; Rytkönen, Seppo; Senar, Juan Carlos; Seppänen, Janne T; da Silva, Luís P; Slagsvold, Tore; Solonen, Tapio; Sorace, Alberto; Stenning, Martyn J; Török, János; Tryjanowski, Piotr; van Noordwijk, Arie J; von Numers, Mikael; Walankiewicz, Wiesław; Lambrechts, Marcel M

    2014-01-01

    Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes. PMID:25478150

  16. Social waves in giant honeybees (Apis dorsata) elicit nest vibrations.

    Science.gov (United States)

    Kastberger, Gerald; Weihmann, Frank; Hoetzl, Thomas

    2013-07-01

    Giant honeybees (Apis dorsata) nest in the open and have developed a wide array of strategies for colony defence, including the Mexican wave-like shimmering behaviour. In this collective response, the colony members perform upward flipping of their abdomens in coordinated cascades across the nest surface. The time-space properties of these emergent waves are response patterns which have become of adaptive significance for repelling enemies in the visual domain. We report for the first time that the mechanical impulse patterns provoked by these social waves and measured by laser Doppler vibrometry generate vibrations at the central comb of the nest at the basic (='natural') frequency of 2.156 ± 0.042 Hz which is more than double the average repetition rate of the driving shimmering waves. Analysis of the Fourier spectra of the comb vibrations under quiescence and arousal conditions provoked by mass flight activity and shimmering waves gives rise to the proposal of two possible models for the compound physical system of the bee nest: According to the elastic oscillatory plate model, the comb vibrations deliver supra-threshold cues preferentially to those colony members positioned close to the comb. The mechanical pendulum model predicts that the comb vibrations are sensed by the members of the bee curtain in general, enabling mechanoreceptive signalling across the nest, also through the comb itself. The findings show that weak and stochastic forces, such as general quiescence or diffuse mass flight activity, cause a harmonic frequency spectrum of the comb, driving the comb as an elastic plate. However, shimmering waves provide sufficiently strong forces to move the nest as a mechanical pendulum. This vibratory behaviour may support the colony-intrinsic information hypothesis herein that the mechanical vibrations of the comb provoked by shimmering do have the potential to facilitate immediate communication of the momentary defensive state of the honeybee nest to

  17. Reproductive ecology of American Oystercatchers nesting on shell rakes

    Science.gov (United States)

    Jodice, Patrick G.; Thibault, Janet M.; Collins, S.A.; Spinks, Mark D.; Sanders, Felicia J.

    2014-01-01

    Degradation of nesting habitat for coastal birds has led to the use of nontraditional nesting habitat. The American Oystercatcher (Haematopus palliatus) is listed as a "Species of High Concern'' by the U. S. Shorebird Conservation Plan and is declining in the southern portion of its U. S. breeding range, where ~ 50% of breeding oystercatchers nest on shell substrate instead of beachfront habitat. We measured daily survival rates during incubation and chick rearing in shell rake habitats over five breeding seasons in the Cape Romain region of South Carolina, USA. Of 354 nesting attempts monitored, 16.1% hatched at least one egg. During incubation, daily survival rate was 0.938, corresponding to 22.8% success to hatching (nest success). For broods, daily survival was 0.991, or 74.0% success from hatching to fledging. Productivity in the Cape Romain region is primarily being lost during the incubation phase, when nests are exposed to overwash and predation. Mobile chicks may, however, be able to avoid flood events or predators by relocating to higher or more protected portions of a shell rake. Based on comparative data for American Oystercatchers from elsewhere in their range, it does not appear that shell rakes in the Cape Romain region are inferior breeding habitat. Our data suggest that conservation actions targeting nest and chick loss from flooding and predation have the greatest opportunity to enhance reproductive success in this core breeding area, and that an assessment of the availability, structure, avian use, and protection status of shell rakes is warranted.

  18. Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

    Directory of Open Access Journals (Sweden)

    Marie-Andrée Giroux

    2016-08-01

    Full Text Available Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter “conspicuous behaviour”, as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

  19. Variation in clutch size in relation to nest size in birds

    NARCIS (Netherlands)

    Møller, Anders P.; Adriaensen, Frank; Artemyev, Alexandr; Bańbura, Jerzy; Barba, Emilio; Biard, Clotilde; Blondel, Jacques; Bouslama, Zihad; Bouvier, Jean-Charles; Camprodon, Jordi; Cecere, Francesco; Charmantier, Anne; Charter, Motti; Cichoń, Mariusz; Cusimano, Camillo; Czeszczewik, Dorota; Demeyrier, Virginie; Doligez, Blandine; Doutrelant, Claire; Dubiec, Anna; Eens, Marcel; Eeva, Tapio; Faivre, Bruno; Ferns, Peter N.; Forsman, Jukka T.; García-Del-Rey, Eduardo; Goldshtein, Aya; Goodenough, Anne E.; Gosler, Andrew G.; Góźdź, Iga; Grégoire, Arnaud; Gustafsson, Lars; Hartley, Ian R.; Heeb, Philipp; Hinsley, Shelley A.; Isenmann, Paul; Jacob, Staffan; Järvinen, Antero; Juškaitis, Rimvydas; Korpimäki, Erkki; Krams, Indrikis; Laaksonen, Toni; Leclercq, Bernard; Lehikoinen, Esa; Loukola, Olli; Lundberg, Arne; Mainwaring, Mark C.; Mänd, Raivo; Massa, Bruno; Mazgajski, Tomasz D.; Merino, Santiago; Mitrus, Cezary; Mönkkönen, Mikko; Morales-Fernaz, Judith; Morin, Xavier; Nager, Ruedi G.; Nilsson, Jan-Åke; Nilsson, Sven G.; Norte, Ana C.; Orell, Markku; Perret, Philippe; Pimentel, Carla S.; Pinxten, Rianne; Priedniece, Ilze; Quidoz, Marie-Claude; Remeš, Vladimir; Richner, Heinz; Robles, Hugo; Rytkönen, Seppo; Senar, Juan Carlos; Seppänen, Janne T.; da Silva, Luís P.; Slagsvold, Tore; Solonen, Tapio; Sorace, Alberto; Stenning, Martyn J.; Török, János; Tryjanowski, Piotr; van Noordwijk, Arie J.; von Numers, Mikael; Walankiewicz, Wiesław; Lambrechts, Marcel M.

    2014-01-01

    Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of

  20. Predicting nest success from habitat features in aspen forests of the central Rocky Mountains

    Science.gov (United States)

    Heather M. Struempf; Deborah M. Finch; Gregory Hayward; Stanley Anderson

    2001-01-01

    We collected nesting data on bird use of aspen stands in the Routt and Medicine Bow National Forests between 1987 and 1989. We found active nest sites of 28 species of small nongame birds on nine study plots in undisturbed aspen forests. We compared logistic regression models predicting nest success (at least one nestling) from nest-site or stand-level habitat...

  1. Male Rock Sparrow (Petronia petronia) Nest Defence Correlates with Female Ornament Size

    DEFF Research Database (Denmark)

    Griggio, Matteo; Matessi, Giuliano; Pilastro, Andrea

    2003-01-01

    We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d-old nest...

  2. Breeding phenology of birds: mechanisms underlying seasonal declines in the risk of nest predation.

    Directory of Open Access Journals (Sweden)

    Kathi L Borgmann

    Full Text Available Seasonal declines in avian clutch size are well documented, but seasonal variation in other reproductive parameters has received less attention. For example, the probability of complete brood mortality typically explains much of the variation in reproductive success and often varies seasonally, but we know little about the underlying cause of that variation. This oversight is surprising given that nest predation influences many other life-history traits and varies throughout the breeding season in many songbirds. To determine the underlying causes of observed seasonal decreases in risk of nest predation, we modeled nest predation of Dusky Flycatchers (Empidonax oberholseri in northern California as a function of foliage phenology, energetic demand, developmental stage, conspecific nest density, food availability for nest predators, and nest predator abundance. Seasonal variation in the risk of nest predation was not associated with seasonal changes in energetic demand, conspecific nest density, or predator abundance. Instead, seasonal variation in the risk of nest predation was associated with foliage density (early, but not late, in the breeding season and seasonal changes in food available to nest predators. Supplemental food provided to nest predators resulted in a numerical response by nest predators, increasing the risk of nest predation at nests that were near supplemental feeders. Our results suggest that seasonal changes in foliage density and factors associated with changes in food availability for nest predators are important drivers of temporal patterns in risk of avian nest predation.

  3. Assessing nest-building behavior of mice using a 3D depth camera.

    Science.gov (United States)

    Okayama, Tsuyoshi; Goto, Tatsuhiko; Toyoda, Atsushi

    2015-08-15

    We developed a novel method to evaluate the nest-building behavior of mice using an inexpensive depth camera. The depth camera clearly captured nest-building behavior. Using three-dimensional information from the depth camera, we obtained objective features for assessing nest-building behavior, including "volume," "radius," and "mean height". The "volume" represents the change in volume of the nesting material, a pressed cotton square that a mouse shreds and untangles in order to build its nest. During the nest-building process, the total volume of cotton fragments is increased. The "radius" refers to the radius of the circle enclosing the fragments of cotton. It describes the extent of nesting material dispersion. The "radius" averaged approximately 60mm when a nest was built. The "mean height" represents the change in the mean height of objects. If the nest walls were high, the "mean height" was also high. These features provided us with useful information for assessment of nest-building behavior, similar to conventional methods for the assessment of nest building. However, using the novel method, we found that JF1 mice built nests with higher walls than B6 mice, and B6 mice built nests faster than JF1 mice. Thus, our novel method can evaluate the differences in nest-building behavior that cannot be detected or quantified by conventional methods. In future studies, we will evaluate nest-building behaviors of genetically modified, as well as several inbred, strains of mice, with several nesting materials.

  4. Effect of conductivity variations within the electric double layer on the streaming potential estimation in narrow fluidic confinements.

    Science.gov (United States)

    Das, Siddhartha; Chakraborty, Suman

    2010-07-06

    In this article, we investigate the implications of ionic conductivity variations within the electrical double layer (EDL) on the streaming potential estimation in pressure-driven fluidic transport through narrow confinements. Unlike the traditional considerations, we do not affix the ionic conductivities apriori by employing preset values of dimensionless parameters (such as the Dukhin number) to estimate the streaming potential. Rather, utilizing the Gouy-Chapman-Grahame model for estimating the electric potential and charge density distribution within the Stern layer, we first quantify the Stern layer electrical conductivity as a function of the zeta potential and other pertinent parameters quantifying the interaction of the ionic species with the charged surface. Next, by invoking the Boltzmann model for cationic and anionic distribution within the diffuse layer, we obtain the diffuse layer electrical conductivity. On the basis of these two different conductivities pertaining to the two different portions of the EDL as well as the bulk conductivity, we define two separate Dukhin numbers that turn out to be functions of the dimensionless zeta potential and the channel height to Debye length ratio. We derive analytical expressions for the streaming potential as a function of the fundamental governing parameters, considering the above. The results reveal interesting and significant deviations between the streaming potential predictions from the present considerations against the corresponding predictions from the classical considerations in which electrochemically consistent estimates of variable EDL conductivity are not traditionally accounted for. In particular, it is revealed that the variations of streaming potential with zeta potential are primarily determined by the competing effects of EDL electromigration and ionic advection. Over low and high zeta potential regimes, the Stern layer and diffuse layer conductivities predominantly dictate the streaming

  5. Correlates of nest-defense behavior of common terns

    Science.gov (United States)

    Erwin, R.M.

    1988-01-01

    Nest-defense behavior was studied at seven Common Tern (Sterna hirundo) colonies in southern coastal New Jersey during June and July 1981. Data were collected weekly on numbers of adults, nests, eggs, and young in relation to the frequency and intensity of dive attacks on a human intruder by nesting terns. I explored the relationships between attack behavior and colony size/density, seasonality, and brood survival. The results provide little support for social facilitation since neither colony size (range 30-250 nests) nor density was related to mean attack frequency; however, in larger colonies, fewer birds participated in dive attacks. Although the intensity of attacks was strongly seasonal, patterns were very different among colonies and peak attack rates did not always coincide with peak hatching periods. Defense levels declined late in the season in most colonies regardless of whether brood survival was high or low. Colonies with individuals that attacked early in the season had higher overall nesting success than in colonies where individuals showed little early season aggression.

  6. Commitments to aggression and nest sites in male Betta splendens.

    Science.gov (United States)

    Bronstein, P M

    1981-06-01

    Male Siamese fighting fish construct nests that are relatively isolated from conspecific males. Following nest construction, the presence of a male opponent elicits (a) nest fixation, (b) further nest building, and (c) Betta's agonistic sequence, i.e., attacks alternating with flight movements, along with gill displays occurring near the opponent. The form of a male-male encounter depends upon the distance between a resident's nest and the opponent as well as upon the individual differences in combatants' tolerance for the presence of a conspecific nearby. Also, the intensity of aggression early in an encounter is positively correlated with the intensity of subsequent fighting. Male Bettas appear to compete for space through the use of aggressive behavior and to coordinate their fighting activities by means of visual signals. An incentive model of visual communication is proposed in which visual cues emanating from a displaying male opponent elicit attack with an intensity that is directly proportional to the persistence of the opponent and inversely proportional to the distance between fish.

  7. Hydrodynamic modeling of Singapore's coastal waters: Nesting and model accuracy

    Science.gov (United States)

    Hasan, G. M. Jahid; van Maren, Dirk Sebastiaan; Ooi, Seng Keat

    2016-01-01

    The tidal variation in Singapore's coastal waters is influenced by large-scale, complex tidal dynamics (by interaction of the Indian Ocean and the South China Sea) as well as monsoon-driven low frequency variations, requiring a model with large spatial coverage. Close to the shores, the complex topography, influenced by headlands and small islands, requires a high resolution model to simulate tidal dynamics. This can be achieved through direct nesting or multi-scale nesting, involving multiple model grids. In this paper, we investigate the effect of grid resolution and multi-scale nesting on the tidal dynamics in Singapore's coastal waters, by comparing model results with observations using different statistical techniques. The results reveal that the intermediate-scale model is generally sufficiently accurate (equal to or better than the most refined model), but also that the most refined model is only more accurate when nested in the intermediate scale model (requiring multi-scale nesting). This latter is the result of the complex tidal dynamics around Singapore, where the dominantly diurnal tidal currents are decoupled from the semi-diurnal water level variations. Furthermore, different techniques to quantify model accuracy (harmonic analysis, basic statistics and more complex statistics) are inconsistent in determining which model is more accurate.

  8. Does habitat fragmentation influence nest predation in the shortgrass prairie?

    Science.gov (United States)

    Howard, M.N.; Skagen, S.K.; Kennedy, P.L.

    2001-01-01

    We examined the effects of habitat fragmentation and vegetation structure of shortgrass prairie and Conservation Reserve Program (CRP) lands on predation rates of artificial and natural nests in northeastern Colorado. The CRP provides federal payments to landowners to take highly erodible cropland out of agricultural production. In our study area, CRP lands have been reseeded primarily with non-native grasses, and this vegetation is taller than native shortgrass prairie. We measured three indices of habitat fragmentation (patch size, degree of matrix fragmentation, and distance from edge), none of which influenced mortality rates of artificial or natural nests. Vegetation structure did influence predation rates of artificial nests; daily mortality decreased significantly with increasing vegetation height. Vegetation structure did not influence predation rates of natural nests. CRP lands and shortgrass sites did not differ with respect to mortality rates of artificial nests. Our study area is only moderately fragmented; 62% of the study area is occupied by native grassland. We conclude that the extent of habitat fragmentation in our study area does not result in increased predation in remaining patches of shortgrass prairie habitat.

  9. Homing to nest baskets by wild female mallards

    Science.gov (United States)

    Doty, H.A.; Lee, F.B.

    1974-01-01

    A high rate of homing to nest baskets by adult female mallards (Anas platyrhynchos) was observed in prairie potholes of North Dakota. One hundred and thirteen female mallards were caught on nest baskets, banded, and marked with nasal saddles. Forty-six percent homed at least once to nest baskets in the marshes where they were previously captured. Two-thirds of the returnees were observed in the same baskets where they had been caught. The observed rate of homing by previously successful nesters (52 percent) was significantly (P old ducklings that hatched in nest baskets were recaptured as nesting adults in baskets. Five of these hens returned to their natal marshes, and two others were found within 2 km of their natal marshes. Band recovery data indicated that 91 percent of the hunting mortality occurred within 10 km of the banding locations. Information on estimated rate of annual survival and the observed rate of homing suggests that nearly all surviving marked adults returned to within 10 km of the marshes where they were banded.

  10. Semi-automated bacterial spore detection system with micro-fluidic chips for aerosol collection, spore treatment and ICAN DNA detection.

    Science.gov (United States)

    Inami, Hisao; Tsuge, Kouichiro; Matsuzawa, Mitsuhiro; Sasaki, Yasuhiko; Togashi, Shigenori; Komano, Asuka; Seto, Yasuo

    2009-07-15

    A semi-automated bacterial spore detection system (BSDS) was developed to detect biological threat agents (e.g., Bacillus anthracis) on-site. The system comprised an aerosol sampler, micro-fluidic chip-A (for spore germination and cell lysis), micro-fluidic chip-B (for extraction and detection of genomic DNA) and an analyzer. An aerosol with bacterial spores was first collected in the collection chamber of chip-A with a velocity of 300 l/min, and the chip-A was taken off from the aerosol sampler and loaded into the analyzer. Reagents packaged in the chip-A were sequentially applied into the chamber. The genomic DNA extract from spore lyzate was manually transferred from chip-A to chip-B and loaded into the analyzer. Genomic DNA in chip-B was first trapped on a glass bead column, washed with various reagents, and eluted to the detection chamber by sequential auto-dispensing. Isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) with fluorescent measurement was adopted to amplify and detect target DNA. Bacillus subtilis was the stimulant of biological warfare agent in this experiment. Pretreatment conditions were optimized by examining bacterial target DNA recovery in the respective steps (aerosol collection, spore germination, cell lysis, and DNA extraction), by an off-chip experiment using a real-time polymerase chain reaction quantification method. Without the germination step, B. subtilis spores did not demonstrate amplification of target DNA. The detection of 10(4) spores was achieved within 2h throughout the micro-fluidic process.

  11. Lifespan analyses of forest raptor nests: patterns of creation, persistence and reuse.

    Science.gov (United States)

    Jiménez-Franco, María V; Martínez, José E; Calvo, José F

    2014-01-01

    Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts.

  12. Exploring Multi-Modal Distributions with Nested Sampling

    CERN Document Server

    Feroz, F

    2013-01-01

    In performing a Bayesian analysis, two difficult problems often emerge. First, in estimating the parameters of some model for the data, the resulting posterior distribution may be multi-modal or exhibit pronounced (curving) degeneracies. Secondly, in selecting between a set of competing models, calculation of the Bayesian evidence for each model is computationally expensive using existing methods such as thermodynamic integration. Nested Sampling is a Monte Carlo method targeted at the efficient calculation of the evidence, but also produces posterior inferences as a by-product and therefore provides means to carry out parameter estimation as well as model selection. The main challenge in implementing Nested Sampling is to sample from a constrained probability distribution. One possible solution to this problem is provided by the Galilean Monte Carlo (GMC) algorithm. We show results of applying Nested Sampling with GMC to some problems which have proven very difficult for standard Markov Chain Monte Carlo (MC...

  13. Characterising equilibrium logic and nested logic programs: Reductions and complexity

    CERN Document Server

    Pearce, David; Woltran, Stefan

    2009-01-01

    Equilibrium logic is an approach to nonmonotonic reasoning that extends the stable-model and answer-set semantics for logic programs. In particular, it includes the general case of nested logic programs, where arbitrary Boolean combinations are permitted in heads and bodies of rules, as special kinds of theories. In this paper, we present polynomial reductions of the main reasoning tasks associated with equilibrium logic and nested logic programs into quantified propositional logic, an extension of classical propositional logic where quantifications over atomic formulas are permitted. We provide reductions not only for decision problems, but also for the central semantical concepts of equilibrium logic and nested logic programs. In particular, our encodings map a given decision problem into some formula such that the latter is valid precisely in case the former holds. The basic tasks we deal with here are the consistency problem, brave reasoning, and skeptical reasoning. Additionally, we also provide encoding...

  14. Nest architecture shapes the collective behaviour of harvester ants.

    Science.gov (United States)

    Pinter-Wollman, Noa

    2015-10-01

    Structures influence how individuals interact and, therefore, shape the collective behaviours that emerge from these interactions. Here I show that the structure of a nest influences the collective behaviour of harvester ant colonies. Using network analysis, I quantify nest architecture and find that as chamber connectivity and redundancy of connections among chambers increase, so does a colony's speed of recruitment to food. Interestingly, the volume of the chambers did not influence speed of recruitment, suggesting that the spatial organization of a nest has a greater impact on collective behaviour than the number of workers it can hold. Thus, by changing spatial constraints on social interactions organisms can modify their behaviour and impact their fitness.

  15. Welfare indicators in laying hens in relation to nest exclusion

    DEFF Research Database (Denmark)

    Alm, M; Tauson, R; Holm, L

    2016-01-01

    . The assessed indicators were: corticosterone metabolites in droppings (FCM), corticosterone concentration in yolk, corticosterone concentration in plasma, irregularities of eggshells, heterophil to lymphocyte (H:L) ratio, tonic immobility duration, and feather cover. Behavioral observations showed...... that the birds had a clear preference for using the secluded nest sites, confirming that they were likely to perceive nest exclusion as an undesirable experience. Further, elevated levels of FCM in droppings, yolk corticosterone concentrations, H:L ratios and irregular eggshells were detected in both nest...... between FCM in droppings and eggshell irregularities, also supporting the use of eggshell irregularities as a potential non-invasive welfare indicator. However, the pattern of the stress response varied between indicators and correlations were generally few and inconsistent, highlighting the complexity...

  16. Factors affecting detection of burrowing owl nests during standardized surveys

    Science.gov (United States)

    Conway, C.J.; Garcia, V.; Smith, M.D.; Hughes, K.

    2008-01-01

    Identifying causes of declines and evaluating effects of management practices on persistence of local populations of burrowing owls (Athene cunicularia) requires accurate estimates of abundance and population trends. Moreover, regulatory agencies in the United States and Canada typically require surveys to detect nest burrows prior to approving developments or other activities in areas that are potentially suitable for nesting burrowing owls. In general, guidelines on timing of surveys have been lacking and surveys have been conducted at different times of day and in different stages of the nesting cycle. We used logistic regression to evaluate 7 factors that could potentially affect probability of a surveyor detecting a burrowing owl nest. We conducted 1,444 detection trials at 323 burrowing owl nests within 3 study areas in Washington and Wyoming, USA, between February and August 2000-2002. Detection probability was highest during the nestling period and increased with ambient temperature. The other 5 factors that we examined (i.e., study area, time of day, timing within the breeding season, wind speed, % cloud cover) interacted with another factor to influence detection probability. Use of call-broadcast surveys increased detection probability, even during daylight hours when we detected >95% of owls visually. Optimal timing of surveys will vary due to differences in breeding phenology and differences in nesting behavior across populations. Nevertheless, we recommend ???3 surveys per year: one that coincides with the laying and incubation period, another that coincides with the early nestling period, and a third that coincides with the late nestling period. In northern latitudes, surveys can be conducted throughout the day.

  17. Fleas (Siphonaptera) in the Nests of Dormice (Gliridae: Rodentia) in Lithuania.

    Science.gov (United States)

    Lipatova, I; Stanko, M; Paulauskas, A; Spakovaite, S; Gedminas, V

    2015-05-01

    Negative effects of flea (Siphonaptera) parasitism on the host may be expressed in different ways. The aim of this study was to assess distribution of the flea fauna in nests of dormice in Lithuania. Nests of Glis glis (L.), Dryomys nitedula (Pallas), and Muscardinus avellanarius (L.) were collected from nest boxes in 2012 and 2013. Fleas were collected from nests in the laboratory and put into plastic tubes with 70% ethanol. Flea species were identified using morphological keys. From 400 nest boxes, 112 nests of dormice were collected from eight sites from mixed forests of central Lithuania. Twenty-three nests of G. glis were collected from nest boxes, with 16 of them containing 286 fleas belonging to four species: Ceratophyllus sciurorum (Schrank) (259), C. gallinae (Schrank) (23), Hystrichopsylla talpae (Curtis) (3), and Megabothris turbidus (Rothschild) (1). Fourteen nests of M. avellanarius were collected from nest boxes, 4 of which contained 224 fleas belonging to two species: C. sciurorum (221) and C. gallinae (3). Twenty-four nests of D. nitedula were collected from nest boxes, including 17 containing 207 fleas belonging to two species: C. sciurorum (205) and C. gallinae (2). Fifty-one nests of undetermined dormice species also were collected from nest boxes, 12 of them contained 395 fleas belonging to three species: C. sciurorum (374), Ctenophthalmus agyrtes (Heller) (19), and Ctenophthalmus assimilis (Taschenberg) (2). C. sciurorum was a predominant species in the nests of dormice. The occurrence of C. gallinae was documented in Lithuania for the first time.

  18. Coping with shifting nest predation refuges by European reed Warblers Acrocephalus scirpaceus.

    Directory of Open Access Journals (Sweden)

    Lucyna Halupka

    Full Text Available Predation, the most important source of nest mortality in altricial birds, has been a subject of numerous studies during past decades. However, the temporal dynamics between changing predation pressures and parental responses remain poorly understood. We analysed characteristics of 524 nests of European reed warblers monitored during six consecutive breeding seasons in the same area, and found some support for the shifting nest predation refuge hypothesis. Nest site characteristics were correlated with nest fate, but a nest with the same nest-site attributes could be relatively safe in one season and vulnerable to predation in another. Thus nest predation refuges were ephemeral and there was no between-season consistency in nest predation patterns. Reed warblers that lost their first nests in a given season did not disperse farther for the subsequent reproductive attempt, compared to successful individuals, but they introduced more changes to their second nest sites. In subsequent nests, predation risk remained constant for birds that changed nest-site characteristics, but increased for those that did not. At the between-season temporal scale, individual birds did not perform better with age in terms of reducing nest predation risk. We conclude that the experience acquired in previous years may not be useful, given that nest predation refuges are not stable.

  19. Pseudoxylaria as stowaway of the fungus-growing termite nest:

    DEFF Research Database (Denmark)

    Visser, Anna A.; Kooij, Pepijn Wilhelmus; Debets, Alfons J. M.

    2011-01-01

    Though inconspicuous in healthy nests, Pseudoxylaria species are almost always present and overgrow deteriorating fungus-growing termite gardens. Whether these fungi are detrimental to the fungus-garden, benign, or even beneficial is unclear. We hypothesize that Pseudoxylaria is a stowaway...... that practices a sit-and-wait strategy to survive in the termite nest. Using isolates from three different termite genera to test our hypothesis, we compared Pseudoxylaria’s growth on 40 carbon sources with that of Termitomyces and tested its interaction with Termitomyces. The C-source use of both fungi largely...

  20. Imperfect nesting and transport properties in unconventional density waves

    Science.gov (United States)

    Dóra, Balázs; Maki, Kazumi; Virosztek, Attila

    2002-10-01

    We consider the effect of imperfect nesting in quasi-one-dimensional unconventional density waves (DW's). The phase diagram is very close to those in a conventional DW's. The linear and non-linear aspects of the electric conductivity are discussed. At T=0 the frequency dependent electric conductivity develops a small dip at low frequencies. The threshold electric field depends strongly on the imperfect nesting parameter, allowing us to describe very well the measured threshold electric field in the low temperature phase of the quasi-two-dimensional organic conductor, α-(BEDT-TTF)2KHg(SCN)4.

  1. Efficient use of iterative solvers in nested topology optimization

    DEFF Research Database (Denmark)

    Amir, Oded; Stolpe, Mathias; Sigmund, Ole

    2010-01-01

    In the nested approach to structural optimization, most of the computational effort is invested in the solution of the analysis equations. In this study, it is suggested to reduce this computational cost by using an approximation to the solution of the analysis problem, generated by a Krylov...... subspace iterative solver. By choosing convergence criteria for the iterative solver that are strongly related to the optimization objective and to the design sensitivities, it is possible to terminate the iterative solution of the nested equations earlier compared to traditional convergence measures...

  2. Don't Mess with the NEST

    Energy Technology Data Exchange (ETDEWEB)

    Larson, M

    2012-03-15

    NEST stands for Nuclear Emergency Support Team. The NEST Mission Statement as first established: (1) Conduct, direct, coordinate search and recovery operations for nuclear material, weapons or devices; and (2) Assist in identification and deactivation of Improvised Nuclear Devices (INDs) and Radiological Dispersal Devices (RDDs). Then in 1980 a very sophisticated improvised explosive device was found at Harvey's Casino at Lake Tahoe, Nevada. The FBI and Bomb Squads were unprepared and it detonated. As a result the additional phrase 'and Sophisticated Improvised Explosive Devices (SIEDs)' was added to the Mission Statement.

  3. Automated micro fluidic system for PCR applications in the monitoring of drinking water quality; Aplicacion de sistemas bionaliticos integrados sobre plataformas de microfluidica en el control de la calidad microbiologica del agua

    Energy Technology Data Exchange (ETDEWEB)

    Soria Soria, E.; Yanez Amoros, A.; Murtula Corbi, R.; Catalan Cuenca, V.; Martin-Cisneros, C. S.; Ymbern, O.; Alonso-Chamorro, J.

    2009-07-01

    Microbiological laboratories present a growing interest in automated, simple and user-friendly methodologies able to perform simultaneous analysis of a high amount of samples. Analytical tools based on micro-fluidic could play an important role in this field. In this work, the development of an automated micro fluidic system for PCR applications and aimed to monitoring of drinking water quality is presented. The device will be able to determine, simultaneously, fecal pollution indicators and water-transmitted pathogens. Further-more, complemented with DNA pre-concentration and extraction modules, the device would present a highly integrated solution for microbiological diagnostic laboratories. (Author) 13 refs.

  4. The path to the nest of spiders The path to the nest of spiders

    Directory of Open Access Journals (Sweden)

    Eliane Luz Bayer

    2008-04-01

    Full Text Available Italo Calvino writes in his preface to The Path to the Nest of Spiders that the novel answers to the "ripeness of the time" since ht wrote it after wartime, a period when everyone had a tale to tell. He tells us that this is a story in which iobody is a hero and nobody has the class consciousness necessary to unify them in the struggle. Calvino acknowledges that it was difficult to conciliate his experiences with the postwar literary movement which he calls Neo-expresSionism, a term which, he thinks, describes better Italian Neo-realism. This is a book with a full realistic depictior of the incongruousness of the whole situation, showing rumen beings driven by loneliness, aggressiveness, unfulfilment and failure to meet, their nerves frayed by the War. It reveals human beings in their weaknesses, subjected to deterministic fates changing roles according to circumstance. Partisans shift to the Nazi side and inform on their f rmer allies and vice-versa, being later chased in revenge. The novel has as its setting Italy under Fascism and unde German occupation, the Italian people being divided betw en the fascists of the "Black Brigade" and the "Partisa4s" who belonged to the Resistance. Although this is a pOlitical book, it has universal appeal. At the same time that it livens up historical facts about the period, it moves our feelings. Calvino's book is about World War II as it is viewed and felt by a small outcast, Pin, who makes considerable efforts to be accepted and understood by adults. In his daily life Pinsuffers the consequences Of the war. His aggressive disposition reflects the environment which he has been brought up in: since he was born, his country has been at war. Besides that, his only sister is a whore, whom he hates and despises. Italo Calvino writes in his preface to The Path to the Nest of Spiders that the novel answers to the "ripeness of the time" since ht wrote it after wartime, a period when everyone had a tale to tell

  5. A unique nest-protection strategy in a new species of spider wasp.

    Directory of Open Access Journals (Sweden)

    Michael Staab

    Full Text Available Hymenoptera show a great variation in reproductive potential and nesting behavior, from thousands of eggs in sawflies to just a dozen in nest-provisioning wasps. Reduction in reproductive potential in evolutionary derived Hymenoptera is often facilitated by advanced behavioral mechanisms and nesting strategies. Here we describe a surprising nesting behavior that was previously unknown in the entire animal kingdom: the use of a vestibular cell filled with dead ants in a new spider wasp (Hymenoptera: Pompilidae species collected with trap nests in South-East China. We scientifically describe the 'Bone-house Wasp' as Deuteragenia ossarium sp. nov., named after graveyard bone-houses or ossuaries. We show that D. ossarium nests are less vulnerable to natural enemies than nests of other sympatric trap-nesting wasps, suggesting an effective nest protection strategy, most likely by utilizing chemical cues emanating from the dead ants.

  6. Nesting Biology and Behavior of Euodynerus dantici (Rossi, 1790 (Hymenoptera: Vespidae: Eumeninae in Central Mongolia

    Directory of Open Access Journals (Sweden)

    Batchuluun Buyanjargal

    2015-12-01

    Full Text Available Nesting biology of Euodynerus dantici (Rossi, 1790 was studied in the Khugnu- Khaan Mountains of Khugnu-Tarna National Park, central Mongolia in 2014 using nest traps. Euodynerus dantici is univoltine in the study site, with one generation per growth season. Nest architecture and its structural parts were described in details. The inner cells of the nests were longer and contained a proportionately larger amount of food than the shorter outer cells. Females developed in inner cells and males developed in outer cells. Developmental stages of E. dantici is studied with details of pupation period. All basic behavioral elements of nesting females are described. A nest parasitoid, Chrysis ignita (Linnaeus, 1758 (Hymenoptera, Chrysididae was reared from E. dantici nests for the fi rst time. For provisioning, caterpillars of the family Noctuidae (Lepidoptera were hunted by females. Diversity in nest architecture is possibly a result of nest parasite pressure

  7. Multilevel Analysis Methods for Partially Nested Cluster Randomized Trials

    Science.gov (United States)

    Sanders, Elizabeth A.

    2011-01-01

    This paper explores multilevel modeling approaches for 2-group randomized experiments in which a treatment condition involving clusters of individuals is compared to a control condition involving only ungrouped individuals, otherwise known as partially nested cluster randomized designs (PNCRTs). Strategies for comparing groups from a PNCRT in the…

  8. Xylaria species associated with nests of Odontotermes formosanus in Taiwan.

    Science.gov (United States)

    Ju, Yu-Ming; Hsieh, Huei-Mei

    2007-01-01

    Nine species of Xylaria were collected in Taiwan from nests of Odontotermes formosanus, the only known macrotermitine termite in Taiwan. These include six newly described species, X. acuminatilongissima, X. atrodivaricata, X. brunneovinosa, X. griseosepiacea, X. intraflava and X. ochraceostroma, and three previously known species, X. cirrata, X. escharoidea and X. nigripes. We obtained cultures and ITS sequences from the nine species found in Taiwan and describe anamorphs for eight of them. Before the current study teleomorph-anamorph connections in the Xylaria species associated with termite nests have been established unequivocally in X. escharoidea only. Xylaria angulosa, X. fimbriata, X. kedahae, X. micrura, X. radicans, X. reinkingii and X. tolosa also are considered and annotated because they were reported to grow on ground and likely are associated with termite nests. Epitypifications are made for X. cirrata, X. escharoidea and X. nigripes. Xylaria sanchezii is considered a nomen dubium. Photographs are presented for most of the aforementioned species. A dichotomous key to 25 Xylaria species growing on termite nests or ground also is given.

  9. Multi-Core Nested Depth-First Search

    NARCIS (Netherlands)

    Laarman, Alfons; Langerak, Rom; Pol, van de Jaco; Weber, Michael; Wijs, Anton; Bultan, T.; Hsiung, P.-A.

    2011-01-01

    The LTL Model Checking problem is reducible to finding accepting cycles in a graph. The Nested Depth-First Search (NDFS) algorithm detects accepting cycles efficiently: on-the-fly, with linear-time complexity and negligible memory overhead. The only downside of the algorithm is that it relies on an

  10. Improved Multi-Core Nested Depth-First Search

    NARCIS (Netherlands)

    Evangelista, Sami; Laarman, Alfons; Petrucci, Laure; Pol, van de Jaco; Ramesh, S.

    2012-01-01

    This paper presents CNDFS, a tight integration of two earlier multi-core nested depth-first search (NDFS) algorithms for LTL model checking. CNDFS combines the different strengths and avoids some weaknesses of its predecessors. We compare CNDFS to an earlier ad-hoc combination of those two algorithm

  11. Repeatability in nest construction by male three-spined sticklebacks

    NARCIS (Netherlands)

    Rushbrook, B. J.; Dingemanse, N. J.; Barber, I.

    Structures built by animals may convey useful information about the builder that may be used by conspecifics in quality assessment. In fish, nest construction has been suggested to reflect qualities of individual builders, but little is known about how consistent individual differences are over

  12. Sea turtle nesting distributions and oceanographic constraints on hatchling migration.

    Science.gov (United States)

    Putman, Nathan F; Bane, John M; Lohmann, Kenneth J

    2010-12-07

    Patterns of abundance across a species's reproductive range are influenced by ecological and environmental factors that affect the survival of offspring. For marine animals whose offspring must migrate long distances, natural selection may favour reproduction in areas near ocean currents that facilitate migratory movements. Similarly, selection may act against the use of potential reproductive areas from which offspring have difficulty emigrating. As a first step towards investigating this conceptual framework, we analysed loggerhead sea turtle (Caretta caretta) nest abundance along the southeastern US coast as a function of distance to the Gulf Stream System (GSS), the ocean current to which hatchlings in this region migrate. Results indicate that nest density increases as distance to the GSS decreases. Distance to the GSS can account for at least 90 per cent of spatial variation in regional nest density. Even at smaller spatial scales, where local beach conditions presumably exert strong effects, at least 38 per cent of the variance is explained by distance from the GSS. These findings suggest that proximity to favourable ocean currents strongly influences sea turtle nesting distributions. Similar factors may influence patterns of abundance across the reproductive ranges of diverse marine animals, such as penguins, eels, salmon and seals.

  13. Nested structures approach for bulk 3D negative index materials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2009-01-01

    We propose a generic conceptual idea to obtain bulk 3D negative index metamaterials, which exhibit isotropic properties. The design is based on the nested structures approach, when one element providing magnetic response is inserted into another design with negative dielectric constant. Both...

  14. Using Gesture to Teach Seneca in a Language Nest School

    Science.gov (United States)

    Borgia, Melissa Elayne

    2014-01-01

    Seneca elder Sandy Dowdy and her granddaughter Autumn Crouse direct a language nest school for children aged two to five years in a small longhouse-shaped building, "Ganöhsesge:kha:' Hë:nödeyë:sta'":, or the Faithkeepers School, on the Seneca Allegany Territory in upstate New York. They practice immersion teaching and use forms of…

  15. Behavior of greedy sparse representation algorithms on nested supports

    DEFF Research Database (Denmark)

    Mailhé, Boris; Sturm, Bob L.; Plumbley, Mark

    2013-01-01

    We study the links between recovery properties of Orthogonal Matching Pursuit (OMP) and the whole General MP class for sparse signals with nested supports, i.e., supports that share an inclusion relationship. In particular, we show that the support recovery optimality of those algorithms is not l...

  16. Nested Genetic Algorithm for Resolving Overlapped Spectral Bands

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A nested genetic algorithm, including genetic parameter level and genetic implemented level for peak parameters, was proposed and applied for resolving overlapped spectral bands. By the genetic parameter level, parameters of genetic algorithm were optimized; moreover, the number of overlapped peaks was determined simultaneously. Then parameters of individual peaks were computed with the genetic implemented level.

  17. NEST-SITE SELECTION IN THE CAPE SUGARBIRD We dedicate ...

    African Journals Online (AJOL)

    to fluctuations in wind-speed, an average value was determined for five .... where k is a constant (6,17 x 10-8) having units so that Hc is in cal em-I min-l (porter ...... predators constitute a major force limiting birds nesting on or near the ground.

  18. Urine Nested Polymerase Chain Reaction in Neonatal Septicemia.

    Science.gov (United States)

    Das, B K; Suri, Shipra; Nath, Gopal; Prasad, Rajniti

    2015-08-01

    This cross-sectional study was done to evaluate diagnostic efficacy of urine nested polymerase chain reaction (PCR) using broad-range 16SrDNA PCR-based amplification, followed by restriction analysis and sequencing in neonatal septicemia. The study included 50 babies; 48% had vaginal delivery, 46% were preterm, 20% had a history of prolonged rupture of membranes and 56% were low birth weight (≤2500 g). Clinical presentations were lethargy (96%), respiratory distress (80%) and bleeding diathesis (16%). Absolute neutrophil count <1800/mm(3) was observed in 60%, and positive C-reactive protein in 46%. Thirty neonates had positive blood culture, and Klebsiella pneumoniae (22%) was the predominant organism. Nested urine PCR was positive in 38 (76%) and detected bacterial DNA in 8 neonates with negative blood cultures. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of nested PCR were 100, 60, 78.9, 100 and 84%, respectively, compared with blood culture. Nested PCR can detect most bacteria in single assay and identify unusual and unexpected causal agents.

  19. Comparison of nest shapes and densities of two sympatric species ...

    African Journals Online (AJOL)

    Comparison of nest shapes and densities of two sympatric species of ... there are significant, though small, differences in height, diameter, number of caps, surface ... the addition of a first cap decreases the volume/surface ratio but a second or ...

  20. Improved Multi-Core Nested Depth-First Search

    NARCIS (Netherlands)

    Evangelista, Sami; Laarman, Alfons; Petrucci, Laure; van de Pol, Jan Cornelis; Ramesh, S.

    2012-01-01

    This paper presents CNDFS, a tight integration of two earlier multi-core nested depth-first search (NDFS) algorithms for LTL model checking. CNDFS combines the different strengths and avoids some weaknesses of its predecessors. We compare CNDFS to an earlier ad-hoc combination of those two